HL7 FHIR® US Core Implementation Guide (Release 3.0.1 STU3 Update for Comment)

This page is part of the US Core (v3.0.1: STU3 Ballot 3) based on FHIR R4. The current version which supercedes this version is 5.0.1. For a full list of available versions, see the Directory of published versions

StructureDefinition-us-core-observation-lab

Laboratory results are grouped and summarized using the DiagnosticReport resource which reference Observation resources. Each Observation resource represents an individual laboratory test and result value, a “nested” panel (such as a microbial susceptibility panel) which references other observations, or rarely a laboratory test with component result values. This profile sets minimum expectations for the Observation resource resource to record, search and fetch laboratory test results associated with a patient. It identifies which core elements, extensions, vocabularies and value sets SHALL be present in the resource when using this profile.

Example Usage Scenarios:

The following are example usage scenarios for the US Core-Results profile:

  • Query for lab results belonging to a Patient
  • Record lab results belonging to a Patient

Mandatory and Must Support Data Elements

The following data-elements are mandatory (i.e data MUST be present) or must be supported if the data is present in the sending system (Must Support definition). They are presented below in a simple human-readable explanation. Profile specific guidance and examples are provided as well. The Formal Profile Definition below provides the formal summary, definitions, and terminology requirements.

Each Observation must have:

  1. a status
  2. a category code of ‘laboratory’
  3. a LOINC code, if available, which tells you what is being measured
  4. a patient

Each Observation must support:

  1. a time indicating when the measurement was taken
  2. a result value or a reason why the data is absent
    • if the result value is a numeric quantity, a standard UCUM unit

Profile specific implementation guidance:

  • Additional codes that translate or map to the Observation code or category codes are allowed. For example:
    • providing both a local code and LOINC code
    • providing a more specific category codes such as ‘chemistry’, SNOMED CT concept, or system specific codes in addition to the ‘laboratory’ category code.
  • An Observation without a value, SHALL include a reason why the data is absent unless there are component observations, or references to other Observations that are grouped within it .
  • See the General Guidance Section for further guidance on using UCUM

Examples

Formal Views of Profile Content

Description of Profiles, Differentials, and Snapshots.

The official URL for this profile is: http://hl7.org/fhir/us/core/StructureDefinition/us-core-observation-lab

Published on Mon Aug 19 00:00:00 EDT 2019 as active by the HL7 US Realm Steering Committee.

This profile builds on Observation

Observation

Summary of the Mandatory Requirements

  1. A code in Observation.status with a required binding to ObservationStatus
  2. One or more CodeableConcepts in Observation.category
    • which must have at least a Observation.category = {“coding”: [{“code”: “laboratory”, “system”: “ http://terminology.hl7.org/CodeSystem/observation-category”}]}
  3. A CodeableConcept in Observation.code with an extensible binding to LOINC Codes
  4. A Patient Reference in Observation.subject

Summary of the Must Support Requirements

  1. A dateTime in Observation.effective[x] with the following constraints: Datetime must be at least to day.
  2. A Quantity in Observation.value[x] with the following constraints: SHOULD use Snomed CT for coded Results, SHALL use UCUM for coded quantity units.
  3. A CodeableConcept in Observation.dataAbsentReason with an extensible binding to DataAbsentReason

Summary of Constraints

  1. If Observation.code is the same as an Observation.component.code then the value element associated with the code SHALL NOT be present
  2. dataAbsentReason SHALL only be present if Observation.value[x] is not present
  3. If there is no component or related element then either a value[x] or a data absent reason must be present
  4. Datetime must be at least to day.
  5. SHOULD use Snomed CT for coded Results
  6. SHALL use UCUM for coded quantity units.
NameFlagsCard.TypeDescription & Constraintsdoco
.. Observation I0..*us-core-2: If there is no component or related element then either a value[x] or a data absent reason must be present
... status S1..1codeBinding: ObservationStatus (required)
... category S1..*(Slice Definition)Slice: Unordered, Open by pattern:$this
.... category:Laboratory S1..1CodeableConceptRequired Pattern: At least the following
..... coding1..*CodingCode defined by a terminology system
Fixed Value: (complex)
...... system1..1uriIdentity of the terminology system
Fixed Value: http://terminology.hl7.org/CodeSystem/observation-category
...... code1..1codeSymbol in syntax defined by the system
Fixed Value: laboratory
... code S1..1CodeableConceptLaboratory Test Name
Binding: LOINCCodes (extensible)
... subject S1..1Reference(US Core Patient Profile)
... effective[x] SI0..1us-core-1: Datetime must be at least to day.
.... effectiveDateTimedateTime
.... effectivePeriodPeriod
... value[x] SI0..1Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, PeriodResult Value
us-core-4: SHOULD use Snomed CT for coded Results
us-core-3: SHALL use UCUM for coded quantity units.
... dataAbsentReason SI0..1CodeableConceptBinding: DataAbsentReason (extensible)

doco Documentation for this format
NameFlagsCard.TypeDescription & Constraintsdoco
.. Observation I0..*Measurements and simple assertions
us-core-2: If there is no component or related element then either a value[x] or a data absent reason must be present
... id Σ0..1idLogical id of this artifact
... meta Σ0..1MetaMetadata about the resource
... implicitRules ?!Σ0..1uriA set of rules under which this content was created
... language 0..1codeLanguage of the resource content
Binding: CommonLanguages (preferred)
Max Binding: AllLanguages
... text 0..1NarrativeText summary of the resource, for human interpretation
... contained 0..*ResourceContained, inline Resources
... extension 0..*ExtensionAdditional content defined by implementations
... modifierExtension ?!0..*ExtensionExtensions that cannot be ignored
... identifier Σ0..*IdentifierBusiness Identifier for observation
... basedOn Σ0..*Reference(CarePlan | DeviceRequest | ImmunizationRecommendation | MedicationRequest | NutritionOrder | ServiceRequest)Fulfills plan, proposal or order
... partOf Σ0..*Reference(MedicationAdministration | MedicationDispense | MedicationStatement | Procedure | Immunization | ImagingStudy)Part of referenced event
... status ?!SΣ1..1coderegistered | preliminary | final | amended +
Binding: ObservationStatus (required)
... category S1..*(Slice Definition)Classification of type of observation
Slice: Unordered, Open by pattern:$this
Binding: ObservationCategoryCodes (preferred)
.... category:Laboratory S1..1CodeableConceptClassification of type of observation
Binding: ObservationCategoryCodes (preferred)

Required Pattern: At least the following
..... id0..1stringUnique id for inter-element referencing
..... extension0..*ExtensionAdditional content defined by implementations
..... coding1..*CodingCode defined by a terminology system
Fixed Value: (complex)
...... id0..1stringUnique id for inter-element referencing
...... extension0..*ExtensionAdditional content defined by implementations
...... system1..1uriIdentity of the terminology system
Fixed Value: http://terminology.hl7.org/CodeSystem/observation-category
...... version0..1stringVersion of the system - if relevant
...... code1..1codeSymbol in syntax defined by the system
Fixed Value: laboratory
...... display0..1stringRepresentation defined by the system
...... userSelected0..1booleanIf this coding was chosen directly by the user
..... text0..1stringPlain text representation of the concept
... code SΣ1..1CodeableConceptLaboratory Test Name
Binding: LOINCCodes (extensible)
... subject SΣ1..1Reference(US Core Patient Profile)Who and/or what the observation is about
... focus Σ0..*Reference(Resource)What the observation is about, when it is not about the subject of record
... encounter Σ0..1Reference(Encounter)Healthcare event during which this observation is made
... effective[x] SΣI0..1Clinically relevant time/time-period for observation
us-core-1: Datetime must be at least to day.
.... effectiveDateTimedateTime
.... effectivePeriodPeriod
... issued Σ0..1instantDate/Time this version was made available
... performer Σ0..*Reference(Practitioner | PractitionerRole | Organization | CareTeam | Patient | RelatedPerson)Who is responsible for the observation
... value[x] SΣI0..1Result Value
us-core-4: SHOULD use Snomed CT for coded Results
us-core-3: SHALL use UCUM for coded quantity units.
.... valueQuantityQuantity
.... valueCodeableConceptCodeableConcept
.... valueStringstring
.... valueBooleanboolean
.... valueIntegerinteger
.... valueRangeRange
.... valueRatioRatio
.... valueSampledDataSampledData
.... valueTimetime
.... valueDateTimedateTime
.... valuePeriodPeriod
... dataAbsentReason SI0..1CodeableConceptWhy the result is missing
Binding: DataAbsentReason (extensible)
... interpretation 0..*CodeableConceptHigh, low, normal, etc.
Binding: ObservationInterpretationCodes (extensible)
... note 0..*AnnotationComments about the observation
... bodySite 0..1CodeableConceptObserved body part
Binding: SNOMEDCTBodyStructures (example)
... method 0..1CodeableConceptHow it was done
Binding: ObservationMethods (example)
... specimen 0..1Reference(Specimen)Specimen used for this observation
... device 0..1Reference(Device | DeviceMetric)(Measurement) Device
... referenceRange I0..*BackboneElementProvides guide for interpretation
obs-3: Must have at least a low or a high or text
.... id 0..1stringUnique id for inter-element referencing
.... extension 0..*ExtensionAdditional content defined by implementations
.... modifierExtension ?!Σ0..*ExtensionExtensions that cannot be ignored even if unrecognized
.... low I0..1SimpleQuantityLow Range, if relevant
.... high I0..1SimpleQuantityHigh Range, if relevant
.... type 0..1CodeableConceptReference range qualifier
Binding: ObservationReferenceRangeMeaningCodes (preferred)
.... appliesTo 0..*CodeableConceptReference range population
Binding: ObservationReferenceRangeAppliesToCodes (example)
.... age 0..1RangeApplicable age range, if relevant
.... text 0..1stringText based reference range in an observation
... hasMember Σ0..*Reference(Observation | QuestionnaireResponse | MolecularSequence)Related resource that belongs to the Observation group
... derivedFrom Σ0..*Reference(DocumentReference | ImagingStudy | Media | QuestionnaireResponse | Observation | MolecularSequence)Related measurements the observation is made from
... component ΣI0..*BackboneElementComponent results
.... id 0..1stringUnique id for inter-element referencing
.... extension 0..*ExtensionAdditional content defined by implementations
.... modifierExtension ?!Σ0..*ExtensionExtensions that cannot be ignored even if unrecognized
.... code Σ1..1CodeableConceptType of component observation (code / type)
Binding: LOINCCodes (example)
.... value[x] Σ0..1Actual component result
..... valueQuantityQuantity
..... valueCodeableConceptCodeableConcept
..... valueStringstring
..... valueBooleanboolean
..... valueIntegerinteger
..... valueRangeRange
..... valueRatioRatio
..... valueSampledDataSampledData
..... valueTimetime
..... valueDateTimedateTime
..... valuePeriodPeriod
.... dataAbsentReason I0..1CodeableConceptWhy the component result is missing
Binding: DataAbsentReason (extensible)
.... interpretation 0..*CodeableConceptHigh, low, normal, etc.
Binding: ObservationInterpretationCodes (extensible)
.... referenceRange 0..*Unknown reference to #Observation.referenceRange
Provides guide for interpretation of component result

doco Documentation for this format

Observation

Summary of the Mandatory Requirements

  1. A code in Observation.status with a required binding to ObservationStatus
  2. One or more CodeableConcepts in Observation.category
    • which must have at least a Observation.category = {“coding”: [{“code”: “laboratory”, “system”: “ http://terminology.hl7.org/CodeSystem/observation-category”}]}
  3. A CodeableConcept in Observation.code with an extensible binding to LOINC Codes
  4. A Patient Reference in Observation.subject

Summary of the Must Support Requirements

  1. A dateTime in Observation.effective[x] with the following constraints: Datetime must be at least to day.
  2. A Quantity in Observation.value[x] with the following constraints: SHOULD use Snomed CT for coded Results, SHALL use UCUM for coded quantity units.
  3. A CodeableConcept in Observation.dataAbsentReason with an extensible binding to DataAbsentReason

Summary of Constraints

  1. If Observation.code is the same as an Observation.component.code then the value element associated with the code SHALL NOT be present
  2. dataAbsentReason SHALL only be present if Observation.value[x] is not present
  3. If there is no component or related element then either a value[x] or a data absent reason must be present
  4. Datetime must be at least to day.
  5. SHOULD use Snomed CT for coded Results
  6. SHALL use UCUM for coded quantity units.

Differential View

NameFlagsCard.TypeDescription & Constraintsdoco
.. Observation I0..*us-core-2: If there is no component or related element then either a value[x] or a data absent reason must be present
... status S1..1codeBinding: ObservationStatus (required)
... category S1..*(Slice Definition)Slice: Unordered, Open by pattern:$this
.... category:Laboratory S1..1CodeableConceptRequired Pattern: At least the following
..... coding1..*CodingCode defined by a terminology system
Fixed Value: (complex)
...... system1..1uriIdentity of the terminology system
Fixed Value: http://terminology.hl7.org/CodeSystem/observation-category
...... code1..1codeSymbol in syntax defined by the system
Fixed Value: laboratory
... code S1..1CodeableConceptLaboratory Test Name
Binding: LOINCCodes (extensible)
... subject S1..1Reference(US Core Patient Profile)
... effective[x] SI0..1us-core-1: Datetime must be at least to day.
.... effectiveDateTimedateTime
.... effectivePeriodPeriod
... value[x] SI0..1Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, PeriodResult Value
us-core-4: SHOULD use Snomed CT for coded Results
us-core-3: SHALL use UCUM for coded quantity units.
... dataAbsentReason SI0..1CodeableConceptBinding: DataAbsentReason (extensible)

doco Documentation for this format

Snapshot View

NameFlagsCard.TypeDescription & Constraintsdoco
.. Observation I0..*Measurements and simple assertions
us-core-2: If there is no component or related element then either a value[x] or a data absent reason must be present
... id Σ0..1idLogical id of this artifact
... meta Σ0..1MetaMetadata about the resource
... implicitRules ?!Σ0..1uriA set of rules under which this content was created
... language 0..1codeLanguage of the resource content
Binding: CommonLanguages (preferred)
Max Binding: AllLanguages
... text 0..1NarrativeText summary of the resource, for human interpretation
... contained 0..*ResourceContained, inline Resources
... extension 0..*ExtensionAdditional content defined by implementations
... modifierExtension ?!0..*ExtensionExtensions that cannot be ignored
... identifier Σ0..*IdentifierBusiness Identifier for observation
... basedOn Σ0..*Reference(CarePlan | DeviceRequest | ImmunizationRecommendation | MedicationRequest | NutritionOrder | ServiceRequest)Fulfills plan, proposal or order
... partOf Σ0..*Reference(MedicationAdministration | MedicationDispense | MedicationStatement | Procedure | Immunization | ImagingStudy)Part of referenced event
... status ?!SΣ1..1coderegistered | preliminary | final | amended +
Binding: ObservationStatus (required)
... category S1..*(Slice Definition)Classification of type of observation
Slice: Unordered, Open by pattern:$this
Binding: ObservationCategoryCodes (preferred)
.... category:Laboratory S1..1CodeableConceptClassification of type of observation
Binding: ObservationCategoryCodes (preferred)

Required Pattern: At least the following
..... id0..1stringUnique id for inter-element referencing
..... extension0..*ExtensionAdditional content defined by implementations
..... coding1..*CodingCode defined by a terminology system
Fixed Value: (complex)
...... id0..1stringUnique id for inter-element referencing
...... extension0..*ExtensionAdditional content defined by implementations
...... system1..1uriIdentity of the terminology system
Fixed Value: http://terminology.hl7.org/CodeSystem/observation-category
...... version0..1stringVersion of the system - if relevant
...... code1..1codeSymbol in syntax defined by the system
Fixed Value: laboratory
...... display0..1stringRepresentation defined by the system
...... userSelected0..1booleanIf this coding was chosen directly by the user
..... text0..1stringPlain text representation of the concept
... code SΣ1..1CodeableConceptLaboratory Test Name
Binding: LOINCCodes (extensible)
... subject SΣ1..1Reference(US Core Patient Profile)Who and/or what the observation is about
... focus Σ0..*Reference(Resource)What the observation is about, when it is not about the subject of record
... encounter Σ0..1Reference(Encounter)Healthcare event during which this observation is made
... effective[x] SΣI0..1Clinically relevant time/time-period for observation
us-core-1: Datetime must be at least to day.
.... effectiveDateTimedateTime
.... effectivePeriodPeriod
... issued Σ0..1instantDate/Time this version was made available
... performer Σ0..*Reference(Practitioner | PractitionerRole | Organization | CareTeam | Patient | RelatedPerson)Who is responsible for the observation
... value[x] SΣI0..1Result Value
us-core-4: SHOULD use Snomed CT for coded Results
us-core-3: SHALL use UCUM for coded quantity units.
.... valueQuantityQuantity
.... valueCodeableConceptCodeableConcept
.... valueStringstring
.... valueBooleanboolean
.... valueIntegerinteger
.... valueRangeRange
.... valueRatioRatio
.... valueSampledDataSampledData
.... valueTimetime
.... valueDateTimedateTime
.... valuePeriodPeriod
... dataAbsentReason SI0..1CodeableConceptWhy the result is missing
Binding: DataAbsentReason (extensible)
... interpretation 0..*CodeableConceptHigh, low, normal, etc.
Binding: ObservationInterpretationCodes (extensible)
... note 0..*AnnotationComments about the observation
... bodySite 0..1CodeableConceptObserved body part
Binding: SNOMEDCTBodyStructures (example)
... method 0..1CodeableConceptHow it was done
Binding: ObservationMethods (example)
... specimen 0..1Reference(Specimen)Specimen used for this observation
... device 0..1Reference(Device | DeviceMetric)(Measurement) Device
... referenceRange I0..*BackboneElementProvides guide for interpretation
obs-3: Must have at least a low or a high or text
.... id 0..1stringUnique id for inter-element referencing
.... extension 0..*ExtensionAdditional content defined by implementations
.... modifierExtension ?!Σ0..*ExtensionExtensions that cannot be ignored even if unrecognized
.... low I0..1SimpleQuantityLow Range, if relevant
.... high I0..1SimpleQuantityHigh Range, if relevant
.... type 0..1CodeableConceptReference range qualifier
Binding: ObservationReferenceRangeMeaningCodes (preferred)
.... appliesTo 0..*CodeableConceptReference range population
Binding: ObservationReferenceRangeAppliesToCodes (example)
.... age 0..1RangeApplicable age range, if relevant
.... text 0..1stringText based reference range in an observation
... hasMember Σ0..*Reference(Observation | QuestionnaireResponse | MolecularSequence)Related resource that belongs to the Observation group
... derivedFrom Σ0..*Reference(DocumentReference | ImagingStudy | Media | QuestionnaireResponse | Observation | MolecularSequence)Related measurements the observation is made from
... component ΣI0..*BackboneElementComponent results
.... id 0..1stringUnique id for inter-element referencing
.... extension 0..*ExtensionAdditional content defined by implementations
.... modifierExtension ?!Σ0..*ExtensionExtensions that cannot be ignored even if unrecognized
.... code Σ1..1CodeableConceptType of component observation (code / type)
Binding: LOINCCodes (example)
.... value[x] Σ0..1Actual component result
..... valueQuantityQuantity
..... valueCodeableConceptCodeableConcept
..... valueStringstring
..... valueBooleanboolean
..... valueIntegerinteger
..... valueRangeRange
..... valueRatioRatio
..... valueSampledDataSampledData
..... valueTimetime
..... valueDateTimedateTime
..... valuePeriodPeriod
.... dataAbsentReason I0..1CodeableConceptWhy the component result is missing
Binding: DataAbsentReason (extensible)
.... interpretation 0..*CodeableConceptHigh, low, normal, etc.
Binding: ObservationInterpretationCodes (extensible)
.... referenceRange 0..*Unknown reference to #Observation.referenceRange
Provides guide for interpretation of component result

doco Documentation for this format

Downloads: StructureDefinition: (XML, JSON), Schema: XML Schematron


Quick Start

Below is an overview of the required set of RESTful FHIR interactions - for example, search and read operations - for this profile. See the Conformance requirements for a complete list of supported RESTful interactions for this IG.

  • See the General Guidance section for additional rules and expectations when a server requires status parameters.
  • See the General Guidance section for additional guidance on searching for multiple patients.

Mandatory Search Parameters:

The following search parameters, search parameter combinations SHALL be supported. Any listed search parameter modifiers, comparators, chains and composites SHALL also be supported UNLESS they are listed as “optional” in which case they SHOULD be supported.:

  1. SHALL support searching using the combination of the patient and category search parameters:

    GET [base]/Observation?patient=[reference]&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory

    Example:

    1. GET [base]/Observation?patient=1134281&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory

    Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and a category code = laboratory (how to search by reference and how to search by token)

  2. SHALL support searching using the combination of the patient and code search parameters:
    • including optional support for composite OR search on code (e.g.code={[system]}|[code],{[system]}|[code],...)

    GET [base]/Observation?patient=[reference]&code={[system]}|[code]{,{[system]}|[code],...}

    Example:

    1. GET [base]/Observation?patient=1134281&code=http://loinc.org|2339-0
    2. GET [base]/Observation?patient=1134281&code=http://loinc.org|2339-0,http://loinc.org|25428-4,2514-8

    Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and observation code(s). SHOULD support search by multiple report codes. The Observation code parameter searches `Observation.code only. (how to search by reference and how to search by token)

  3. SHALL support searching using the combination of the patient and category and date search parameters:
    • including support for these date comparators: gt,lt,ge,le
    • including optional support for composite AND search on date (e.g.date=[date]&date=[date]]&...)

    GET [base]/Observation?patient=[reference]&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory&date={gt|lt|ge|le}[date]{&date={gt|lt|ge|le}[date]&...}

    Example:

    1. GET [base]Observation?patient=555580&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory&date=ge2018-03-14

    Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and date and a category code = laboratory (how to search by reference and how to search by token and how to search by date)

Optional Search Parameters:

The following search parameters, search parameter combinations and search parameter modifiers, comparators, chains and composites SHOULD be supported.

  1. SHOULD support searching using the combination of the patient and category and status search parameters:
    • including support for composite OR search on status (e.g.status={[system]}|[code],{[system]}|[code],...)

    GET [base]/Observation?patient=[reference]&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory&status={[system]}|[code]{,{[system]}|[code],...}

    Example:

    1. GET [base]/Observation?patient=1134281&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory&status=final

    Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and category = laboratory and status (how to search by reference and how to search by token)

  2. SHOULD support searching using the combination of the patient and code and date search parameters:
    • including optional support for composite OR search on code (e.g.code={[system]}|[code],{[system]}|[code],...)
    • including support for these date comparators: gt,lt,ge,le
    • including optional support for composite AND search on date (e.g.date=[date]&date=[date]]&...)

    GET [base]/Observation?patient=[reference]&code={[system]}|[code]{,{[system]}|[code],...}&date={gt|lt|ge|le}[date]{&date={gt|lt|ge|le}[date]&...}

    Example:

    1. GET [base]Observation?patient=555580&code=http://loinc.org|2339-0&date=ge2019

    Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and date and report code(s). SHOULD support search by multiple report codes. (how to search by reference and how to search by token and how to search by date)