This page is part of the Personal Health Device FHIR IG (v0.2.0: STU 1 Ballot 2) based on FHIR R4. The current version which supercedes this version is 1.0.0. For a full list of available versions, see the Directory of published versions

StructureDefinition: PhdCompoundNumericObservation - Detailed Descriptions

Definitions for the PhdCompoundNumericObservation Profile.

Observation
Definition

The PhdCompoundNumericObservation reports PHD measurements that contain one of either a Compound-Basic-Nu-Observed-Value, Compound-Simple-Nu-Observed-Value, or Compound-Nu-Observed-Value attribute.

Control0..*
Alternate NamesVital Signs, Measurement, Results, Tests
Comments

Used for compound numeric observations from Personal Health Devices

InvariantsDefined on this element
dom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (: contained.contained.empty())
dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (: contained.where((('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(canonical) = '#').exists()).not()).trace('unmatched', id).empty())
dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (: contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (: contained.meta.security.empty())
dom-6: A resource should have narrative for robust management (: text.div.exists())
obs-6: dataAbsentReason SHALL only be present if Observation.value[x] is not present (: dataAbsentReason.empty() or value.empty())
obs-7: If Observation.code is the same as an Observation.component.code then the value element associated with the code SHALL NOT be present (: value.empty() or component.code.where( (coding.code = %resource.code.coding.code) and (coding.system = %resource.code.coding.system)).empty())
Observation.id
Definition

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

Control0..1
Typeid
Comments

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

Observation.meta
Definition

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

Control1..1
TypeMeta
Observation.meta.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.meta.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.meta.versionId
Definition

The version specific identifier, as it appears in the version portion of the URL. This value changes when the resource is created, updated, or deleted.

Control0..1
Typeid
Comments

The server assigns this value, and ignores what the client specifies, except in the case that the server is imposing version integrity on updates/deletes.

Observation.meta.lastUpdated
Definition

When the resource last changed - e.g. when the version changed.

Control0..1
Typeinstant
Comments

This value is always populated except when the resource is first being created. The server / resource manager sets this value; what a client provides is irrelevant. This is equivalent to the HTTP Last-Modified and SHOULD have the same value on a read interaction.

Observation.meta.source
Definition

A uri that identifies the source system of the resource. This provides a minimal amount of Provenance information that can be used to track or differentiate the source of information in the resource. The source may identify another FHIR server, document, message, database, etc.

Control0..1
Typeuri
Comments

In the provenance resource, this corresponds to Provenance.entity.what[x]. The exact use of the source (and the implied Provenance.entity.role) is left to implementer discretion. Only one nominated source is allowed; for additional provenance details, a full Provenance resource should be used.

This element can be used to indicate where the current master source of a resource that has a canonical URL if the resource is no longer hosted at the canonical URL.

Observation.meta.profile
Definition

A list of profiles (references to StructureDefinition resources) that this resource claims to conform to. The URL is a reference to StructureDefinition.url.

Control0..*
Typecanonical(StructureDefinition)
Comments

It is up to the server and/or other infrastructure of policy to determine whether/how these claims are verified and/or updated over time. The list of profile URLs is a set.

Fixed Valuehttp://hl7.org/fhir/uv/phd/StructureDefinition/PhdCompoundNumericObservation
Observation.meta.security
Definition

Security labels applied to this resource. These tags connect specific resources to the overall security policy and infrastructure.

Control0..1
BindingSecurity Labels from the Healthcare Privacy and Security Classification System.
The codes SHALL be taken from All Security Labels; other codes may be used where these codes are not suitable
TypeCoding
Comments

The security labels can be updated without changing the stated version of the resource. The list of security labels is a set. Uniqueness is based the system/code, and version and display are ignored.

Observation.meta.security.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.meta.security.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.meta.security.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valuehttp://terminology.hl7.org/CodeSystem/v3-ActReason
Observation.meta.security.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.meta.security.code
Definition

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Fixed ValueHTEST
Observation.meta.security.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.meta.security.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.meta.tag
Definition

Tags applied to this resource. Tags are intended to be used to identify and relate resources to process and workflow, and applications are not required to consider the tags when interpreting the meaning of a resource.

Control0..*
BindingCodes that represent various types of tags, commonly workflow-related; e.g. "Needs review by Dr. Jones".
For example codes, see CommonTags
TypeCoding
Comments

The tags can be updated without changing the stated version of the resource. The list of tags is a set. Uniqueness is based the system/code, and version and display are ignored.

Observation.implicitRules
Definition

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

Control0..1
Typeuri
Is Modifiertrue
Comments

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

Observation.language
Definition

The base language in which the resource is written.

Control0..1
BindingA human language.
The codes SHOULD be taken from CommonLanguages
Typecode
Comments

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

Observation.text
Definition

A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

Control0..1
TypeNarrative
Alternate Namesnarrative, html, xhtml, display
Comments

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

Observation.contained
Definition

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

Control0..*
TypeResource
Alternate Namesinline resources, anonymous resources, contained resources
Comments

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

Observation.extension
Definition

An Extension

Control0..1
TypeExtension
Observation.extension.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.extension.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.extension.url
Definition

Source of the definition for the extension code - a logical name or a URL.

Control1..1
Comments

The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

Fixed Valuehttp://hl7.org/fhir/StructureDefinition/observation-gatewayDevice
Observation.extension.valueReference
Definition

Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

Control1..1
TypeReference
Observation.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Control0..*
TypeExtension
Is Modifiertrue
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.identifier(conditionalCreate)
Definition

An identifier created from a combination of the measurement parameters like sensor time stamp, type code, value, units code, patient and device identifiers, and selected elements of any component elements.

NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..1
TypeIdentifier
Requirements

Allows observations to be distinguished in a selective enough manner to prevent resource duplication.

Comments

This value is used in the conditional create to prevent data duplication. PHDs will often re-send already sent data for a variety of reasons. This element is required unless the metric measurement contains no time stamp or is a measurement containing a time stamp that is real time. By real time the time stamp reported by the PHD must be later than the current time reported by the PHD before any measurements are received. There might be other means to ascertain whether the data is real time. Temporarily stored data from IEEE 11073 20601 devices, which are required to delete the data after sending, can also be considered real time. Temporarily stored data from Bluetooth Low Energy Health devices may be resent so these cannot be considered as real time.

Observation.identifier.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.identifier.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.identifier.use
Definition

The purpose of this identifier.

Control0..1
BindingIdentifies the purpose for this identifier, if known .
The codes SHALL be taken from IdentifierUse
Typecode
Is Modifiertrue
Requirements

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

Comments

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

Observation.identifier.type
Definition

A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

Control0..0
BindingA coded type for an identifier that can be used to determine which identifier to use for a specific purpose.
The codes SHALL be taken from Identifier Type Codes; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

Allows users to make use of identifiers when the identifier system is not known.

Comments

This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.

Observation.identifier.system
Definition

Establishes the namespace for the value - that is, a URL that describes a set values that are unique.

Control0..0
Typeuri
Requirements

There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

Comments

Identifier.system is always case sensitive.

Example
General:http://www.acme.com/identifiers/patient
Observation.identifier.value
Definition

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

Control1..1
Typestring
Comments

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

Example
General:123456
Observation.identifier.period
Definition

Time period during which identifier is/was valid for use.

Control0..1
TypePeriod
Observation.identifier.assigner
Definition

Organization that issued/manages the identifier.

Control0..1
TypeReference(Organization)
Comments

The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.

Observation.basedOn
Definition

A plan, proposal or order that is fulfilled in whole or in part by this event. For example, a MedicationRequest may require a patient to have laboratory test performed before it is dispensed.

Control0..*
TypeReference(CarePlan | DeviceRequest | ImmunizationRecommendation | MedicationRequest | NutritionOrder | ServiceRequest)
Requirements

Allows tracing of authorization for the event and tracking whether proposals/recommendations were acted upon.

Alternate NamesFulfills
Observation.partOf
Definition

A larger event of which this particular Observation is a component or step. For example, an observation as part of a procedure.

Control0..*
TypeReference(MedicationAdministration | MedicationDispense | MedicationStatement | Procedure | Immunization | ImagingStudy)
Alternate NamesContainer
Comments

To link an Observation to an Encounter use encounter. See the Notes below for guidance on referencing another Observation.

Observation.status
Definition

The status of the result value. Either 'final' or 'preliminary'

Control1..1
BindingCodes providing the status of an observation.
The codes SHALL be taken from ObservationStatus
Typecode
Is Modifiertrue
Requirements

Need to track the status of individual results. Some results are finalized before the whole report is finalized.

Comments

The value shall be set to 'final' unless a Measurement-Status attribute or Nu-Observed-Value attribute status field indicates that the measurement is preliminary. In that case this field shall be set to 'preliminary'

Observation.category(vitalSignsCategory)
Definition

A code that classifies the general type of observation being made.

Control0..*
BindingCodes for high level observation categories.
The codes SHOULD be taken from ObservationCategoryCodes
TypeCodeableConcept
Requirements

Used for filtering what observations are retrieved and displayed.

Comments

In addition to the required category valueset, this element allows various categorization schemes based on the owner’s definition of the category and effectively multiple categories can be used at once. The level of granularity is defined by the category concepts in the value set.

Observation.category.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.category.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.category.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.category.coding(vitalSigns)
Definition

A reference to a code defined by a terminology system.

Control1..1
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.category.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.category.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.category.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valuehttp://terminology.hl7.org/CodeSystem/observation-category
Observation.category.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.category.coding.code
Definition

The 'vital-signs' category code

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Fixed Valuevital-signs
Observation.category.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.category.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.category.text
Definition

A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.code
Definition

Describes what was observed. Sometimes this is called the observation "name".

Control1..1
BindingCodes identifying names of simple observations.
For example codes, see LOINCCodes
TypeCodeableConcept
Requirements

Knowing what kind of observation is being made is essential to understanding the observation.

Alternate NamesName
Comments

All code-value and, if present, component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Observation.code.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.code.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.code.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.code.coding(MDCType)
Definition

This MDC code expresses what the measurement is

Control1..1
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

For non-compound 11073-20601 metric numeric measurements, this code is obtained from one or more of the Type, Metric-Id, Nu-Observed-Value, and Metric-Id-Partition attributes. The algorithm to get the 16-bit partition and 16-bit term code is as follows: 1. The partition and term code are obtained from the Type attribute. 2. If there is a Metric-Id attribute the term code comes from this attribute. 3. If there is a Nu-Observed-Value attribute the term code comes from this attribute. 4. If the term code is NOT from the Type attribute, and there is a Metric-Id-Partition attribute, the partition comes from this attribute. 5. The 32-bit 11073-10101 code value is given by partition * 2 **16 + term code. It is this value that is placed in the code.coding.code element for this MDCType slice. For compound numeric measurements, the code comes from the Type attribute.

Observation.code.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.code.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.code.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valueurn:iso:std:iso:11073:10101
Observation.code.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.code.coding.code
Definition

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Observation.code.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.code.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.code.coding(LoincCoding)
Definition

This LOINC code expresses what the measurement is

Control0..1
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

If the measurement is one of the magic vital signs, the Magic LOINC code for that vital sign as specified by FHIR appears here.

Observation.code.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.code.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.code.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valuehttp://loinc.org
Observation.code.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.code.coding.code
Definition

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Comments

Required if the measurement is a vital sign

Observation.code.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.code.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.code.text
Definition

A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.subject
Definition

The patient, or group of patients, location, or device this observation is about and into whose record the observation is placed. If the actual focus of the observation is different from the subject (or a sample of, part, or region of the subject), the focus element or the code itself specifies the actual focus of the observation.

Control1..1
TypeReference(Patient | Group | Device | Location)
Requirements

Observations have no value if you don't know who or what they're about.

Comments

One would expect this element to be a cardinality of 1..1. The only circumstance in which the subject can be missing is when the observation is made by a device that does not know the patient. In this case, the observation SHALL be matched to a patient through some context/channel matching technique, and at this point, the observation should be updated.

Observation.subject.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.subject.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.subject.reference
Definition

A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

Control1..1 This element is affected by the following invariants: ref-1
Typestring
Comments

Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

Observation.subject.type
Definition

The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.

The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).

Control0..1
BindingAa resource (or, for logical models, the URI of the logical model).
The codes SHALL be taken from ResourceType; other codes may be used where these codes are not suitable
Typeuri
Comments

This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.

Observation.subject.identifier
Definition

An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..1
TypeIdentifier
Comments

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

Observation.subject.display
Definition

Plain text narrative that identifies the resource in addition to the resource reference.

Control0..1
Typestring
Comments

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

Observation.focus
Definition

The actual focus of an observation when it is not the patient of record representing something or someone associated with the patient such as a spouse, parent, fetus, or donor. For example, fetus observations in a mother's record. The focus of an observation could also be an existing condition, an intervention, the subject's diet, another observation of the subject, or a body structure such as tumor or implanted device. An example use case would be using the Observation resource to capture whether the mother is trained to change her child's tracheostomy tube. In this example, the child is the patient of record and the mother is the focus.

Control0..*
TypeReference(Resource)
Comments

Typically, an observation is made about the subject - a patient, or group of patients, location, or device - and the distinction between the subject and what is directly measured for an observation is specified in the observation code itself ( e.g., "Blood Glucose") and does not need to be represented separately using this element. Use specimen if a reference to a specimen is required. If a code is required instead of a resource use either bodysite for bodysites or the standard extension focusCode.

Observation.encounter
Definition

The healthcare event (e.g. a patient and healthcare provider interaction) during which this observation is made.

Control0..1
TypeReference(Encounter)
Requirements

For some observations it may be important to know the link between an observation and a particular encounter.

Alternate NamesContext
Comments

This will typically be the encounter the event occurred within, but some events may be initiated prior to or after the official completion of an encounter but still be tied to the context of the encounter (e.g. pre-admission laboratory tests).

Observation.effective[x]
Definition

The time or time-period the observed value is asserted as being true. It is a time period if a Measure-Active-Period (duration) attribute is part of the metric measurement sent by the PHD. Otherwise it is the time stamp sent by the PHD or the time of reception by the PHG if the PHD sent no time stamp.

Control1..1
TypeChoice of: dateTime, Period, Timing, instant
[x] NoteSee Choice of Data Types for further information about how to use [x]
Requirements

Knowing when an observation was deemed true is important to its relevance as well as determining trends.

Alternate NamesOccurrence
Comments

At least a date should be present unless this observation is a historical report. For recording imprecise or "fuzzy" times (For example, a blood glucose measurement taken "after breakfast") use the Timing datatype which allow the measurement to be tied to regular life events.

InvariantsDefined on this element
phd-obs-1: Either an effectiveDateTime or effectivePeriod shall be present (: effectiveDateTime.exists() or effectivePeriod.exists().exists())
Observation.issued
Definition

The date and time this version of the observation was made available to providers, typically after the results have been reviewed and verified.

Control0..1
Typeinstant
Comments

For Observations that don’t require review and verification, it may be the same as the lastUpdated time of the resource itself. For Observations that do require review and verification for certain updates, it might not be the same as the lastUpdated time of the resource itself due to a non-clinically significant update that doesn’t require the new version to be reviewed and verified again.

Observation.performer
Definition

Who was responsible for asserting the observed value as "true".

Control0..*
TypeReference(Practitioner | PractitionerRole | Organization | CareTeam | Patient | RelatedPerson)
Requirements

May give a degree of confidence in the observation and also indicates where follow-up questions should be directed.

Observation.value[x]
Definition

The information determined as a result of making the observation, if the information has a simple value.

Control0..0 This element is affected by the following invariants: obs-7
TypeChoice of: Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
[x] NoteSee Choice of Data Types for further information about how to use [x]
Requirements

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Comments

An observation may have; 1) a single value here, 2) both a value and a set of related or component values, or 3) only a set of related or component values. If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

Observation.dataAbsentReason
Definition

Provides a reason why no measurement compoundComponent elements are present. This situation only happens if the Measurement-Status attribute indicates a generic error.

Control0..1 This element is affected by the following invariants: obs-6
BindingCodes specifying why the result (`Observation.value[x]`) is missing.
The codes SHALL be taken from DataAbsentReason; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For many results it is necessary to handle exceptional values in measurements.

Comments

Special values reported in the Compound-Basic/Simple-Nu-Observed-Value are handled individually in each compoundComponent element and are not considered generic. The Compound-Nu-Observed-Value has its own status entry and it is also handled in the component elements representing the compound.

Observation.dataAbsentReason.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.dataAbsentReason.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.dataAbsentReason.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.dataAbsentReason.coding(FhirDefault)
Definition

A reference to a code defined by a terminology system.

Control1..1
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.dataAbsentReason.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.dataAbsentReason.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.dataAbsentReason.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valuehttp://terminology.hl7.org/CodeSystem/data-absent-reason
Observation.dataAbsentReason.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.dataAbsentReason.coding.code
Definition

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Observation.dataAbsentReason.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.dataAbsentReason.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.dataAbsentReason.text
Definition

A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.interpretation
Definition

A categorical assessment of an observation value. For example, high, low, normal.

Control0..*
BindingCodes identifying interpretations of observations.
The codes SHALL be taken from ObservationInterpretationCodes; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Alternate NamesAbnormal Flag
Comments

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Observation.interpretation.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.interpretation.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.interpretation.coding
Definition

A reference to a code defined by a terminology system.

Control0..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.interpretation.coding(MsmtStatusInterpretation)
Definition

A reference to a code defined by a terminology system.

Control0..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.interpretation.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.interpretation.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.interpretation.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valuehttp://hl7.org/fhir/uv/pocd/CodeSystem/measurement-status
Observation.interpretation.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.interpretation.coding.code
Definition

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Observation.interpretation.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.interpretation.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.interpretation.text
Definition

A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.note
Definition

Comments about the observation or the results.

Control0..*
TypeAnnotation
Requirements

Need to be able to provide free text additional information.

Comments

May include general statements about the observation, or statements about significant, unexpected or unreliable results values, or information about its source when relevant to its interpretation.

Observation.bodySite
Definition

Indicates the site on the subject's body where the observation was made (i.e. the target site).

Control0..1
BindingCodes describing anatomical locations. May include laterality.
For example codes, see SNOMEDCTBodyStructures
TypeCodeableConcept
Comments

Only used if not implicit in code found in Observation.code. In many systems, this may be represented as a related observation instead of an inline component.

If the use case requires BodySite to be handled as a separate resource (e.g. to identify and track separately) then use the standard extension bodySite.

Observation.method
Definition

Indicates the mechanism used to perform the observation.

Control0..1
BindingMethods for simple observations.
For example codes, see ObservationMethods
TypeCodeableConcept
Requirements

In some cases, method can impact results and is thus used for determining whether results can be compared or determining significance of results.

Comments

Only used if not implicit in code for Observation.code.

Observation.specimen
Definition

The specimen that was used when this observation was made.

Control0..1
TypeReference(Specimen)
Comments

Should only be used if not implicit in code found in Observation.code. Observations are not made on specimens themselves; they are made on a subject, but in many cases by the means of a specimen. Note that although specimens are often involved, they are not always tracked and reported explicitly. Also note that observation resources may be used in contexts that track the specimen explicitly (e.g. Diagnostic Report).

Observation.device
Definition

The device used to generate the observation data.

Control1..1
TypeReference(Device | DeviceMetric)
Comments

This field will reference the PHD Device.

Observation.device.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.device.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.device.reference
Definition

Reference to the device-related resources that describe the sensor device taking the measurement. This element will point to a Device resource following the Phd Device Profile.

Control1..1 This element is affected by the following invariants: ref-1
Typestring
Comments

This reference points to the Device resource containing information about the sensor device that took the measurement.

Observation.device.type
Definition

The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.

The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).

Control0..1
BindingAa resource (or, for logical models, the URI of the logical model).
The codes SHALL be taken from ResourceType; other codes may be used where these codes are not suitable
Typeuri
Comments

This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.

Observation.device.identifier
Definition

An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..1
TypeIdentifier
Comments

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

Observation.device.display
Definition

Plain text narrative that identifies the resource in addition to the resource reference.

Control0..1
Typestring
Comments

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

Observation.referenceRange
Definition

Guidance on how to interpret the value by comparison to a normal or recommended range. Multiple reference ranges are interpreted as an "OR". In other words, to represent two distinct target populations, two referenceRange elements would be used.

Control0..*
TypeBackboneElement
Requirements

Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

Comments

Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

InvariantsDefined on this element
ele-1: All FHIR elements must have a @value or children (: hasValue() or (children().count() > id.count()))
obs-3: Must have at least a low or a high or text (: low.exists() or high.exists() or text.exists())
Observation.referenceRange.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.referenceRange.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.referenceRange.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Control0..*
TypeExtension
Is Modifiertrue
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content, modifiers
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.referenceRange.low
Definition

The value of the low bound of the reference range. The low bound of the reference range endpoint is inclusive of the value (e.g. reference range is >=5 - <=9). If the low bound is omitted, it is assumed to be meaningless (e.g. reference range is <=2.3).

Control0..1 This element is affected by the following invariants: obs-3
TypeQuantity(SimpleQuantity)
Observation.referenceRange.high
Definition

The value of the high bound of the reference range. The high bound of the reference range endpoint is inclusive of the value (e.g. reference range is >=5 - <=9). If the high bound is omitted, it is assumed to be meaningless (e.g. reference range is >= 2.3).

Control0..1 This element is affected by the following invariants: obs-3
TypeQuantity(SimpleQuantity)
Observation.referenceRange.type
Definition

Codes to indicate the what part of the targeted reference population it applies to. For example, the normal or therapeutic range.

Control0..1
BindingCode for the meaning of a reference range.
The codes SHOULD be taken from ObservationReferenceRangeMeaningCodes
TypeCodeableConcept
Requirements

Need to be able to say what kind of reference range this is - normal, recommended, therapeutic, etc., - for proper interpretation.

Comments

This SHOULD be populated if there is more than one range. If this element is not present then the normal range is assumed.

Observation.referenceRange.appliesTo
Definition

Codes to indicate the target population this reference range applies to. For example, a reference range may be based on the normal population or a particular sex or race. Multiple appliesTo are interpreted as an "AND" of the target populations. For example, to represent a target population of African American females, both a code of female and a code for African American would be used.

Control0..*
BindingCodes identifying the population the reference range applies to.
For example codes, see ObservationReferenceRangeAppliesToCodes
TypeCodeableConcept
Requirements

Need to be able to identify the target population for proper interpretation.

Comments

This SHOULD be populated if there is more than one range. If this element is not present then the normal population is assumed.

Observation.referenceRange.age
Definition

The age at which this reference range is applicable. This is a neonatal age (e.g. number of weeks at term) if the meaning says so.

Control0..1
TypeRange
Requirements

Some analytes vary greatly over age.

Observation.referenceRange.text
Definition

Text based reference range in an observation which may be used when a quantitative range is not appropriate for an observation. An example would be a reference value of "Negative" or a list or table of "normals".

Control0..1
Typestring
Observation.hasMember
Definition

This observation is a group observation (e.g. a battery, a panel of tests, a set of vital sign measurements) that includes the target as a member of the group.

Control0..*
TypeReference(Observation | QuestionnaireResponse | MolecularSequence)
Comments

When using this element, an observation will typically have either a value or a set of related resources, although both may be present in some cases. For a discussion on the ways Observations can assembled in groups together, see Notes below. Note that a system may calculate results from QuestionnaireResponse into a final score and represent the score as an Observation.

Observation.derivedFrom
Definition

The target resource that represents a measurement from which this observation value is derived. For example, a calculated anion gap or a fetal measurement based on an ultrasound image.

Control0..*
TypeReference(DocumentReference | ImagingStudy | Media | QuestionnaireResponse | Observation | MolecularSequence)
Comments

When the PHD reports a time stamp a reference to the Coincident Time Stamp Observation is placed here. When the PHD reports a Source-Handle-Reference/-List attribute the Observation(s) pointed to by that Source-Handle-Reference/-List is (are) placed here. One may end up with several Observation.derivedFrom elements.

Observation.component
Definition

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

Control0..*
TypeBackboneElement
Requirements

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Comments

For a discussion on the ways Observations can be assembled in groups together see Notes below.

InvariantsDefined on this element
ele-1: All FHIR elements must have a @value or children (: hasValue() or (children().count() > id.count()))
Observation.component.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Control0..*
TypeExtension
Is Modifiertrue
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content, modifiers
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code
Definition

Describes what was observed. Sometimes this is called the observation "code".

Control1..1
BindingCodes identifying names of simple observations.
For example codes, see LOINCCodes
TypeCodeableConcept
Requirements

Knowing what kind of observation is being made is essential to understanding the observation.

Comments

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Observation.component.value[x]
Definition

The information determined as a result of making the observation, if the information has a simple value.

Control0..1
TypeChoice of: Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
[x] NoteSee Choice of Data Types for further information about how to use [x]
Requirements

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Comments

Used when observation has a set of component observations. An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

Observation.component.dataAbsentReason
Definition

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

Control0..1 This element is affected by the following invariants: obs-6
BindingCodes specifying why the result (`Observation.value[x]`) is missing.
The codes SHALL be taken from DataAbsentReason; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For many results it is necessary to handle exceptional values in measurements.

Comments

"Null" or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "test not done".

The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Because of these options, use-case agreements are required to interpret general observations for exceptional values.

Observation.component.interpretation
Definition

A categorical assessment of an observation value. For example, high, low, normal.

Control0..*
BindingCodes identifying interpretations of observations.
The codes SHALL be taken from ObservationInterpretationCodes; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Alternate NamesAbnormal Flag
Comments

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Observation.component.referenceRange
Definition

Guidance on how to interpret the value by comparison to a normal or recommended range.

Control0..*
TypeSee Observation.referenceRange
Requirements

Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

Comments

Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

Observation.component(supplementalTypesComponent)
Definition

For each partition:term code pair contained in the Supplemental-Types attribute, a separate supplementalTypesComponent element is generated. The component is not generated if the attribute is absent or empty. The component shall be generated otherwise.

Control0..*
TypeBackboneElement
Requirements

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Comments

A PHD may send a Supplemental-Types attribute as part of the measurement. This attribute consists of a set of MDC nomenclature codes as partition:term code pairs. Each pair is a code describing something additional about the measurement, such as MDC_MODALITY_SPOT in the pulse oximeter which indicates that the provided measurement is a stable average. An MDC_MODALITY_FAST would indicate that a short averaging is used and the result reported regardless of stability.

InvariantsDefined on this element
ele-1: All FHIR elements must have a @value or children (: hasValue() or (children().count() > id.count()))
Observation.component.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Control0..*
TypeExtension
Is Modifiertrue
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content, modifiers
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code
Definition

Describes what was observed. Sometimes this is called the observation "code".

Control1..1
BindingThe codes SHALL be taken from CodeableConcept11073MDC
TypeCodeableConcept
Requirements

Knowing what kind of observation is being made is essential to understanding the observation.

Comments

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Observation.component.code.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.code.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valueurn:iso:std:iso:11073:10101
Observation.component.code.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.component.code.coding.code
Definition

68193 is the 32-bit nomenclature code indicating a 'Supplemental-Types' value

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Fixed Value68193
Observation.component.code.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.component.code.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.component.code.text
Definition

It is recommended to display at least the reference identifier for the Supplemental-Types which is MDC_ATTR_SUPPLEMENTAL_TYPES

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.component.valueCodeableConcept(valueCodeableConcept)
Definition

The information determined as a result of making the observation, if the information is a code.

Control1..1
TypeCodeableConcept
Requirements

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Comments

Used when observation has a set of component observations. An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

Observation.component.valueCodeableConcept.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.valueCodeableConcept.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.valueCodeableConcept.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.valueCodeableConcept.coding(MDCType)
Definition

A reference to a code defined by a terminology system.

Control1..1
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.valueCodeableConcept.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.valueCodeableConcept.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.valueCodeableConcept.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valueurn:iso:std:iso:11073:10101
Observation.component.valueCodeableConcept.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.component.valueCodeableConcept.coding.code
Definition

For the given Supplemental-Types entry the code here is given by: partition * 2**16 + term code

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Observation.component.valueCodeableConcept.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.component.valueCodeableConcept.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.component.valueCodeableConcept.text
Definition

A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.component.dataAbsentReason
Definition

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

Control0..0 This element is affected by the following invariants: obs-6
BindingCodes specifying why the result (`Observation.value[x]`) is missing.
The codes SHALL be taken from DataAbsentReason; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For many results it is necessary to handle exceptional values in measurements.

Comments

"Null" or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "test not done".

The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Because of these options, use-case agreements are required to interpret general observations for exceptional values.

Observation.component.interpretation
Definition

A categorical assessment of an observation value. For example, high, low, normal.

Control0..*
BindingCodes identifying interpretations of observations.
The codes SHALL be taken from ObservationInterpretationCodes; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Alternate NamesAbnormal Flag
Comments

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Observation.component.referenceRange
Definition

Guidance on how to interpret the value by comparison to a normal or recommended range.

Control0..*
TypeSee Observation.referenceRange
Requirements

Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

Comments

Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

Observation.component(relativeTimeComponent)
Definition

This component shall be present if the measurement contains a Relative-Time-Stamp.

Control0..1
TypeBackboneElement
Requirements

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Comments

Relative time stamps are converted to wall clock time by the PHG through the Coincident Time Stamp Observation. The original relative time value shall be provided here in order to recover the data sent by the sensor device. It also provided a higher time resolution than permitted by the effective[x] time stamp should it be needed. The Relative-Time-Stamp is a 32-bit unsigned integer in units of 1/8th ms. It is reported here scaled to microseconds.

InvariantsDefined on this element
ele-1: All FHIR elements must have a @value or children (: hasValue() or (children().count() > id.count()))
Observation.component.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Control0..*
TypeExtension
Is Modifiertrue
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content, modifiers
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code
Definition

Describes what was observed. Sometimes this is called the observation "code".

Control1..1
BindingThe codes SHALL be taken from Quantity11073MDC
TypeCodeableConcept
Requirements

Knowing what kind of observation is being made is essential to understanding the observation.

Comments

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Observation.component.code.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.code.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valueurn:iso:std:iso:11073:10101
Observation.component.code.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.component.code.coding.code
Definition

The MDC code of the Relative-Time-Stamp attribute

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Fixed Value67985
Observation.component.code.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.component.code.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.component.code.text
Definition

The reference identifier should be included in the description. For a Relative-Time-Stamp the ref id is MDC_ATTR_TIME_STAMP_REL

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.component.valueQuantity(valueQuantity)
Definition

The information determined as a result of making the observation, if the information has a simple value.

Control1..1
TypeQuantity
Requirements

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Comments

Used when observation has a set of component observations. An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

Observation.component.valueQuantity.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.valueQuantity.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.valueQuantity.value
Definition

The value of the relative time attribute which is in units of 1/8th milliseconds scaled to microseconds.

Control1..1
Typedecimal
Requirements

Precision is handled implicitly in almost all cases of measurement.

Comments

The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

Observation.component.valueQuantity.comparator
Definition

How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.

Control0..1
BindingHow the Quantity should be understood and represented.
The codes SHALL be taken from QuantityComparator
Typecode
Is Modifiertrue
Requirements

Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

Meaning if MissingIf there is no comparator, then there is no modification of the value
Observation.component.valueQuantity.unit
Definition

A human-readable form of the unit.

Control0..1
Typestring
Requirements

There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

Observation.component.valueQuantity.system
Definition

The unit code shall use the UCUM system

Control1..1 This element is affected by the following invariants: qty-3
Typeuri
Requirements

Need to know the system that defines the coded form of the unit.

Fixed Valuehttp://unitsofmeasure.org
Observation.component.valueQuantity.code
Definition

The UCUM code for microseconds

Control1..1
Typecode
Requirements

Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

Comments

The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency. The context of use may additionally require a code from a particular system.

Fixed Valueus
Observation.component.dataAbsentReason
Definition

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

Control0..0 This element is affected by the following invariants: obs-6
BindingCodes specifying why the result (`Observation.value[x]`) is missing.
The codes SHALL be taken from DataAbsentReason; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For many results it is necessary to handle exceptional values in measurements.

Comments

"Null" or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "test not done".

The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Because of these options, use-case agreements are required to interpret general observations for exceptional values.

Observation.component.interpretation
Definition

A categorical assessment of an observation value. For example, high, low, normal.

Control0..*
BindingCodes identifying interpretations of observations.
The codes SHALL be taken from ObservationInterpretationCodes; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Alternate NamesAbnormal Flag
Comments

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Observation.component.referenceRange
Definition

Guidance on how to interpret the value by comparison to a normal or recommended range.

Control0..*
TypeSee Observation.referenceRange
Requirements

Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

Comments

Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

Observation.component(hiresRelativeTimeComponent)
Definition

This component shall be present if the measurement contains Hi-Res-Relative-Time-Stamp.

Control0..1
TypeBackboneElement
Requirements

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Comments

Hi Res Relative time stamps are converted to wall clock time by the PHG through the Coincident Time Stamp Observation. The original relative time value shall be provided here in order to recover the data sent by the sensor device. It also allows much higher time resolution than permitted in the effective{x] element should it be needed. The Hi-Res-Relative-Time-Stamp is a 64-bit unsigned interger in units of microseconds.

InvariantsDefined on this element
ele-1: All FHIR elements must have a @value or children (: hasValue() or (children().count() > id.count()))
Observation.component.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Control0..*
TypeExtension
Is Modifiertrue
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content, modifiers
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code
Definition

Describes what was observed. Sometimes this is called the observation "code".

Control1..1
BindingThe codes SHALL be taken from Quantity11073MDC
TypeCodeableConcept
Requirements

Knowing what kind of observation is being made is essential to understanding the observation.

Comments

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Observation.component.code.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.code.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valueurn:iso:std:iso:11073:10101
Observation.component.code.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.component.code.coding.code
Definition

The MDC code for the Hi-Res-Relative-Time-Stamp attribute

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Fixed Value68073
Observation.component.code.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.component.code.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.component.code.text
Definition

The reference identifier should be included in the description. For a Hi-Res-Relative-Time-Stamp the ref id is MDC_ATTR_TIME_STAMP_REL_HI_RES

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.component.valueQuantity(valueQuantity)
Definition

The information determined as a result of making the observation, if the information has a simple value.

Control1..1
TypeQuantity
Requirements

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Comments

Used when observation has a set of component observations. An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

Observation.component.valueQuantity.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.valueQuantity.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.valueQuantity.value
Definition

The value of the hi res relative time attribute (already in microseconds).

Control1..1
Typedecimal
Requirements

Precision is handled implicitly in almost all cases of measurement.

Comments

The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

Observation.component.valueQuantity.comparator
Definition

How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.

Control0..1
BindingHow the Quantity should be understood and represented.
The codes SHALL be taken from QuantityComparator
Typecode
Is Modifiertrue
Requirements

Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

Meaning if MissingIf there is no comparator, then there is no modification of the value
Observation.component.valueQuantity.unit
Definition

A human-readable form of the unit.

Control0..1
Typestring
Requirements

There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

Observation.component.valueQuantity.system
Definition

The unit code shall use the UCUM system

Control1..1 This element is affected by the following invariants: qty-3
Typeuri
Requirements

Need to know the system that defines the coded form of the unit.

Fixed Valuehttp://unitsofmeasure.org
Observation.component.valueQuantity.code
Definition

The UCUM code for microseconds

Control1..1
Typecode
Requirements

Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

Comments

The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency. The context of use may additionally require a code from a particular system.

Fixed Valueus
Observation.component.dataAbsentReason
Definition

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

Control0..0 This element is affected by the following invariants: obs-6
BindingCodes specifying why the result (`Observation.value[x]`) is missing.
The codes SHALL be taken from DataAbsentReason; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For many results it is necessary to handle exceptional values in measurements.

Comments

"Null" or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "test not done".

The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Because of these options, use-case agreements are required to interpret general observations for exceptional values.

Observation.component.interpretation
Definition

A categorical assessment of an observation value. For example, high, low, normal.

Control0..*
BindingCodes identifying interpretations of observations.
The codes SHALL be taken from ObservationInterpretationCodes; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Alternate NamesAbnormal Flag
Comments

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Observation.component.referenceRange
Definition

Guidance on how to interpret the value by comparison to a normal or recommended range.

Control0..*
TypeSee Observation.referenceRange
Requirements

Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

Comments

Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

Observation.component(compound)
Definition

Each compoundComponent contains one of the N constituents of the compound measurement. These entries are NOT present if a Measurement-Status attribute indicates an error.

Control0..*
TypeBackboneElement
Requirements

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Comments

A compound measurement is a measurement that requires more than one value to represent it, such as an acceleration which has an x, y, and z components. The Blood pressure is also represented as a compound measurement, containing systolic, diastolic and MAP components. One combines all the compound elements together to describe the measurement. The Metric-Id-List entry n and Compound-Basic/Simple-Nu-Observed-Value entry n are ordered such that the code that describes each entry n is computed from the partition of the Type attribute and the term code of the Metric-Id-List attribute. In the case of the Compound-Nu-Observed-Value, the term code comes from the Compound-Nu-Observed-Value.metric sub-component.

InvariantsDefined on this element
ele-1: All FHIR elements must have a @value or children (: hasValue() or (children().count() > id.count()))
Observation.component.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Control0..*
TypeExtension
Is Modifiertrue
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content, modifiers
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code
Definition

Describes what was observed. Sometimes this is called the observation "code".

Control1..1
BindingThe codes SHALL be taken from 11073MDCnotObject
TypeCodeableConcept
Requirements

Knowing what kind of observation is being made is essential to understanding the observation.

Comments

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Observation.component.code.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.code.coding(MDCType)
Definition

This MDC code expresses what the measurement is

Control0..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.code.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valueurn:iso:std:iso:11073:10101
Observation.component.code.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.component.code.coding.code
Definition

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Observation.component.code.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.component.code.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.component.code.coding(LoincCoding)
Definition

A reference to a code defined by a terminology system.

Control0..1
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.code.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valuehttp://loinc.org
Observation.component.code.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.component.code.coding.code
Definition

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Comments

Required if the measurement is a vital sign

Observation.component.code.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.component.code.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.component.code.text
Definition

It is recommended to display at least the reference identifier describing the compound sub-element

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.component.valueQuantity
Definition

The information determined as a result of making the observation, if the information has a simple value.

Control0..1
TypeQuantity
Requirements

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Comments

Used when observation has a set of component observations. An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

Observation.component.valueQuantity.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.valueQuantity.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.valueQuantity.value
Definition

The value of nth element of the compound attribute. The value element for the nth compoundComponent is missing if the attribute sends a special value or the Compound-Nu-Observed-Value status element indicates an error.

Control1..1
Typedecimal
Requirements

Precision is handled implicitly in almost all cases of measurement.

Comments

The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

Observation.component.valueQuantity.comparator
Definition

How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.

Control0..1
BindingHow the Quantity should be understood and represented.
The codes SHALL be taken from QuantityComparator
Typecode
Is Modifiertrue
Requirements

Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

Meaning if MissingIf there is no comparator, then there is no modification of the value
Observation.component.valueQuantity.unit
Definition

A human-readable form of the unit.

Control0..1
Typestring
Requirements

There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

Observation.component.valueQuantity.system
Definition

The unit code shall use the UCUM system

Control1..1 This element is affected by the following invariants: qty-3
Typeuri
Requirements

Need to know the system that defines the coded form of the unit.

Fixed Valuehttp://unitsofmeasure.org
Observation.component.valueQuantity.code
Definition

The MDC code must be translated to the UCUM code.

Control1..1
Typecode
Requirements

Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

Comments

The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency. The context of use may additionally require a code from a particular system.

Observation.component.dataAbsentReason
Definition

Provides a reason why the expected value in the nth element Observation.compoundComponent.valueQuantity is missing. This could be a NaN (Not a Number), PINF (Positive infinity), NINF (Negative infinity) or the reserved and not-at-this-resolution special values. It can also be indicated by the (measurement) status field of the Compound-Nu-Observed-Value. Note that the FHIR codes for NAN are no longer 'NAN' but 'not-a-number'. Similar changes have been made for NINF and PINF.

Control0..1 This element is affected by the following invariants: obs-6
BindingCodes specifying why the result (`Observation.value[x]`) is missing.
The codes SHALL be taken from DataAbsentReason; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For many results it is necessary to handle exceptional values in measurements.

Comments

"Null" or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "test not done".

The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Because of these options, use-case agreements are required to interpret general observations for exceptional values.

Observation.component.dataAbsentReason.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.dataAbsentReason.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.dataAbsentReason.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.dataAbsentReason.coding(FhirDefault)
Definition

A reference to a code defined by a terminology system.

Control1..1
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.dataAbsentReason.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.dataAbsentReason.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.dataAbsentReason.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valuehttp://terminology.hl7.org/CodeSystem/data-absent-reason
Observation.component.dataAbsentReason.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.component.dataAbsentReason.coding.code
Definition

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Observation.component.dataAbsentReason.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.component.dataAbsentReason.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.component.dataAbsentReason.text
Definition

A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.component.interpretation
Definition

A categorical assessment of an observation value. For example, high, low, normal.

Control0..*
BindingCodes identifying interpretations of observations.
The codes SHALL be taken from ObservationInterpretationCodes; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Alternate NamesAbnormal Flag
Comments

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Observation.component.interpretation.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.interpretation.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.interpretation.coding
Definition

A reference to a code defined by a terminology system.

Control0..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.interpretation.coding(MsmtStatusInterpretation)
Definition

A reference to a code defined by a terminology system.

Control0..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.interpretation.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.interpretation.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.interpretation.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valuehttp://hl7.org/fhir/uv/pocd/CodeSystem/measurement-status
Observation.component.interpretation.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.component.interpretation.coding.code
Definition

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Observation.component.interpretation.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.component.interpretation.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.component.interpretation.text
Definition

A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.component.referenceRange
Definition

Guidance on how to interpret the value by comparison to a normal or recommended range.

Control0..*
TypeSee Observation.referenceRange
Requirements

Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

Comments

Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

Observation.component(accuracyComponent)
Definition

This component shall be present if the Accuracy attribute is present.

Control0..1
TypeBackboneElement
Requirements

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Comments

For a discussion on the ways Observations can be assembled in groups together see Notes below.

InvariantsDefined on this element
ele-1: All FHIR elements must have a @value or children (: hasValue() or (children().count() > id.count()))
Observation.component.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Control0..*
TypeExtension
Is Modifiertrue
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content, modifiers
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code
Definition

Describes what was observed. Sometimes this is called the observation "code".

Control1..1
BindingThe codes SHALL be taken from Quantity11073MDC
TypeCodeableConcept
Requirements

Knowing what kind of observation is being made is essential to understanding the observation.

Comments

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Observation.component.code.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Comments

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Observation.component.code.coding.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.code.coding.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.code.coding.system
Definition

The identification of the code system that defines the meaning of the symbol in the code.

Control1..1
Typeuri
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Comments

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

Fixed Valueurn:iso:std:iso:11073:10101
Observation.component.code.coding.version
Definition

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Comments

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

Observation.component.code.coding.code
Definition

The code for the Accuracy attribute is 67914

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Fixed Value67914
Observation.component.code.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

Control0..1
Typestring
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Observation.component.code.coding.userSelected
Definition

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

Control0..1
Typeboolean
Requirements

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Comments

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

Observation.component.code.text
Definition

Should include the reference identifier for the Accuracy attribute MDC_ATTR_NU_ACCUR_MSMT

Control0..1
Typestring
Requirements

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Comments

Very often the text is the same as a displayName of one of the codings.

Observation.component.valueQuantity(valueQuantity)
Definition

The information determined as a result of making the observation, if the information has a simple value.

Control1..1
TypeQuantity
Requirements

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Comments

Used when observation has a set of component observations. An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

Observation.component.valueQuantity.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Control0..1
Typestring
Observation.component.valueQuantity.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control0..*
TypeExtension
Alternate Namesextensions, user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Observation.component.valueQuantity.value
Definition

This is the value of the accuracy attribute. The value is Mder FLOAT encoded and shall be expressed to the precision indicated by the Mder FLOAT.

Control1..1
Typedecimal
Requirements

Precision is handled implicitly in almost all cases of measurement.

Comments

The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

Observation.component.valueQuantity.comparator
Definition

How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.

Control0..1
BindingHow the Quantity should be understood and represented.
The codes SHALL be taken from QuantityComparator
Typecode
Is Modifiertrue
Requirements

Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

Meaning if MissingIf there is no comparator, then there is no modification of the value
Observation.component.valueQuantity.unit
Definition

A human-readable form of the unit.

Control0..1
Typestring
Requirements

There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

Observation.component.valueQuantity.system
Definition

The unit code shall use the UCUM system

Control1..1 This element is affected by the following invariants: qty-3
Typeuri
Requirements

Need to know the system that defines the coded form of the unit.

Fixed Valuehttp://unitsofmeasure.org
Observation.component.valueQuantity.code
Definition

The units for the Accuracy are given by the units of the measurement so this entry shall have the same code as in Observation.valueQuantity.code

Control1..1
Typecode
Requirements

Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

Comments

The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency. The context of use may additionally require a code from a particular system.

Observation.component.dataAbsentReason
Definition

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

Control0..0 This element is affected by the following invariants: obs-6
BindingCodes specifying why the result (`Observation.value[x]`) is missing.
The codes SHALL be taken from DataAbsentReason; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For many results it is necessary to handle exceptional values in measurements.

Comments

"Null" or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "test not done".

The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Because of these options, use-case agreements are required to interpret general observations for exceptional values.

Observation.component.interpretation
Definition

A categorical assessment of an observation value. For example, high, low, normal.

Control0..*
BindingCodes identifying interpretations of observations.
The codes SHALL be taken from ObservationInterpretationCodes; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Alternate NamesAbnormal Flag
Comments

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Observation.component.referenceRange
Definition

Guidance on how to interpret the value by comparison to a normal or recommended range.

Control0..*
TypeSee Observation.referenceRange
Requirements

Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

Comments

Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.