A record of a request for a diagnostic investigation service to be performed.

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

The only time that a resource does not have an id is when it is being submitted to the server using a create operation. Bundles always have an id, though it is usually a generated UUID.

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

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content.

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 as much as possible.

The base language in which the resource is written.

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).

A human-readable narrative that contains a summary of the resource, and may 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.

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative.

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.

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.

An Extension

• unordered
• Open
• discriminators: url

Non-ordering practitioner, to whom the orderer instructs the recipient to send the results of the request.

unique id for the element within a resource (for internal references).

May be used to represent additional information that is not part of the basic definition of the element. In order 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.

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.

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

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 should be version specific. This will ideally be the URI for the Resource Profile defining the extension, with the code for the extension after a #.

Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).

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. Usually modifier elements provide negation or qualification. In order 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.

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.

Who or what the investigation is to be performed on. This is usually a human patient, but diagnostic tests can also be requested on animals, groups of humans or animals, devices such as dialysis machines, or even locations (typically for environmental scans).

The practitioner that holds legal responsibility for ordering the investigation.

Identifiers assigned to this order by the order or by the receiver.

unique id for the element within a resource (for internal references).

May be used to represent additional information that is not part of the basic definition of the element. In order 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.

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.

The purpose of this identifier.

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

This is labeled as "Is Modifier" because applications should not mistake a temporary id for a permanent one. Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

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

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

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.

Placer URI.

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

Placer Identifier.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986.

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

Organization that issued/manages the identifier.

The reference may be just a text description of the assigner.

An encounter that provides additional information about the healthcare context in which this request is made.

An explanation or justification for why this diagnostic investigation is being requested.

This may be used to decide how the diagnostic investigation will be performed, or even if it will be performed at all.

Additional clinical information about the patient or specimen that may influence test interpretations.

This information includes diagnosis, clinical findings and other observations. Examples include reporting the amount of inspired carbon dioxide for blood gasses, the point in the menstrual cycle for cervical pap tests, and other conditions that influence test interpretations.

• unordered
• Open
• discriminators: @Profile, @type

Additional clinical information about the patient or specimen that may influence test interpretations.

This information includes diagnosis, clinical findings and other observations. Examples include reporting the amount of inspired carbon dioxide for blood gasses, the point in the menstrual cycle for cervical pap tests, and other conditions that influence test interpretations.

One or more specimens that the diagnostic investigation is about.

Many investigation requests will create a need for specimens, but the request itself is not actually about the specimens. This is provided for when the diagnostic investigation is requested on already existing specimens.

The status of the order.

Typically the system placing the order sets the status to requested. Thereafter, the order is maintained by the receiver that updates the status as the request is handled.

The clinical priority associated with this order.

The Order resource also has a priority. Generally, these should be the same, but they can be different, for instance in the case where the clinician indicates that the order is urgent, but the subsequent workflow process overrule this priority for some reason. The effective default value is "normal".

A summary of the events of interest that have occurred as the request is processed. E.g. when the order was made, various processing steps (specimens received), when it was completed.

This is not the same as an audit trail - it is a view of the important things that happened in the past. Typically, there would only be one entry for any given status, and systems may not record all the status events.

unique id for the element within a resource (for internal references).

May be used to represent additional information that is not part of the basic definition of the element. In order 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.

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.

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 that contains it. Usually modifier elements provide negation or qualification. In order 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.

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.

The status for the event.

Additional information about the event that occurred - e.g. if the status remained unchanged.

unique id for the element within a resource (for internal references).

May be used to represent additional information that is not part of the basic definition of the element. In order 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.

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.

A reference to a code defined by a terminology system.

Allows for translations and alternate encodings within a code system. Also supports communication of the same instance to systems requiring different encodings.

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the V3 Core Principles for more information. Ordering of codings is undefined and SHALL not be used to infer meaning.

unique id for the element within a resource (for internal references).

May be used to represent additional information that is not part of the basic definition of the element. In order 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.

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.

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

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

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 de-reference to some definition that establish the system clearly and unambiguously.

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.

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.

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).

Need to refer to a particular code in the system.

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

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

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

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

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations.

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.

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.

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

The date/time at which the event occurred.

The person who was responsible for performing or recording the action.

The specific diagnostic investigations that are requested as part of this request. Sometimes, there can only be one item per request, but in most contexts, more than one investigation can be requested.

There would always be at least one item in normal usage, but this is optional so that a workflow can quote order details without having to list the items.

unique id for the element within a resource (for internal references).

May be used to represent additional information that is not part of the basic definition of the element. In order 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.

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.

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 that contains it. Usually modifier elements provide negation or qualification. In order 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.

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.

The laboratory test, panel or battery that was ordered.

Many laboratory tests and radiology tests embed the specimen/organ system in the test name, for example, serum or serum/plasma glucose, or a chest xray. The specimen may not be recorded separately from the test code.

unique id for the element within a resource (for internal references).

May be used to represent additional information that is not part of the basic definition of the element. In order 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.

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.

A reference to a code defined by a terminology system.

Allows for translations and alternate encodings within a code system. Also supports communication of the same instance to systems requiring different encodings.

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the V3 Core Principles for more information. Ordering of codings is undefined and SHALL not be used to infer meaning.

unique id for the element within a resource (for internal references).

May be used to represent additional information that is not part of the basic definition of the element. In order 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.

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.

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

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

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 de-reference to some definition that establish the system clearly and unambiguously.

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.

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.

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).

Need to refer to a particular code in the system.

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

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

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

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

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations.

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.

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.

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

If the item is related to a specific specimen.

A single specimen should not appear in both DiagnosticOrder.specimen and DiagnosticOrder.item.specimen.

Anatomical location where the request test should be performed. This is the target site.

The status of this individual item within the order.

If the request has multiple items that have their own life cycles, then the items will have their own status while the overall diagnostic order is (usually) "in-progress".

A summary of the events of interest that have occurred as this item of the request is processed.