US Core Implementation Guide
8.0.0 - STU 8 United States of America flag

US Core Implementation Guide, published by HL7 International / Cross-Group Projects. This guide is not an authorized publication; it is the continuous build for version 8.0.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/US-Core/ and changes regularly. See the Directory of published versions

Resource Profile: US Core BMI Profile

Official URL: http://hl7.org/fhir/us/core/StructureDefinition/us-core-bmi Version: 8.0.0
Standards status: Trial-use Computable Name: USCoreBMIProfile
Other Identifiers: OID:2.16.840.1.113883.4.642.40.2.42.10

Copyright/Legal: Used by permission of HL7 International, all rights reserved Creative Commons License

The US Core BMI Profile inherits from the US Core Vital Signs Profile. This profile sets minimum expectations for the Observation resource to record, search, and fetch Body Mass Index (BMI) observations with a standard LOINC codes and UCUM units of measure. It specifies which additional core elements, extensions, vocabularies, and value sets SHALL be present in the resource and constrains how the elements are used. Providing the floor for standards development for specific use cases promotes interoperability and adoption.

Example Usage Scenarios:

The following are example usage scenarios for this profile:

  • Query for body mass index (BMI) observations
  • Record or update body mass index (BMI) observations

Mandatory and Must Support Data Elements

In addition to the Mandatory and Must Support data elements in the US Core Vital Signs Profile, the following data elements must always be present (Mandatory definition) 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 Views below provides the formal summary, definitions, and terminology requirements.
Note that the "Differential Table" displays elements unique to this profile and the "Key Elements Table” displays a combined view of elements for this profile and the US Core Vital Signs Profile.

Each Observation Must Have:

  1. a patient
  2. a fixed code for body mass index (BMI)

Each Observation Must Support:

  1. a result value

Profile Specific Implementation Guidance:

  • The observations MAY have additional codes that translate or map to the Observation code or category codes. For example:
    • providing a local system-specific code
    • providing more specific codes such as 8306-3 - Body height - lying in addition to 8302-2 - Body height. Several additional observation codes are provided in the FHIR core specification vital signs table.

    A code system value SHOULD be supplied for each additional code.

  • The observations MAY have component observations. For example, to qualify the vital sign observation, 8310-5 - Body temperature, 8327-9 - Body temperature measurement site (oral, forehead, rectal, etc.) may be used as a component observation. The FHIR core specification vital signs table provides several of these.
  • *An Observation without a value, SHALL include a reason why the data is absent unless there are 1) component observations, or 2) reporting panel observations using Observation.hasMember.
    • For further guidance, see the Observation Grouping section in FHIR Specification.
    • Systems that never provide an observation without a value are not required to support Observation.dataAbsentReason.
  • *An Observation.component without a value, SHALL include a reason why the data is absent.
    • Systems that never provide a component observation without a component value are not required to support Observation.component.dataAbsentReason.

  • Implementers may use this profile as a base for other vital signs in addition to those in this guide.

  • See the US Core Pediatric BMI for Age Observation Profile for representing pediatric BMI measurements as a percentile based upon growth chart tables.

Usage:

Changes since version 7.0.0:

  • No changes

    • Formal Views of Profile Content

    Description of Profiles, Differentials, Snapshots and how the different presentations work.

    NameFlagsCard.TypeDescription & Constraintsdoco
    .. Observation C 0..* USCoreVitalSignsProfile US Core Body Mass Index (BMI) Profile
    dom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources
    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
    dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated
    dom-5: If a resource is contained in another resource, it SHALL NOT have a security label
    dom-6: A resource should have narrative for robust management
    obs-6: dataAbsentReason SHALL only be present if Observation.value[x] is not present
    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
    vs-2: If there is no component or hasMember element then either a value[x] or a data absent reason must be present.
    ... implicitRules ?!Σ 0..1 uri A set of rules under which this content was created
    ele-1: All FHIR elements must have a @value or children
    ... modifierExtension ?! 0..* Extension Extensions that cannot be ignored
    ele-1: All FHIR elements must have a @value or children
    ext-1: Must have either extensions or value[x], not both
    ... status ?!SΣ 1..1 code registered | preliminary | final | amended +
    Binding: ObservationStatus (required)
    ele-1: All FHIR elements must have a @value or children
    ... Slices for category S 1..* CodeableConcept Classification of type of observation
    Slice: Unordered, Open by value:coding.code, value:coding.system
    Binding: ObservationCategoryCodes (preferred): Codes for high level observation categories.


    ele-1: All FHIR elements must have a @value or children
    .... category:VSCat S 1..1 CodeableConcept Classification of type of observation
    Binding: ObservationCategoryCodes (preferred): Codes for high level observation categories.


    ele-1: All FHIR elements must have a @value or children
    ..... coding SΣ 1..* Coding Code defined by a terminology system
    ele-1: All FHIR elements must have a @value or children
    ...... system SΣ 1..1 uri Identity of the terminology system
    ele-1: All FHIR elements must have a @value or children
    Fixed Value: http://terminology.hl7.org/CodeSystem/observation-category
    ...... code SΣ 1..1 code Symbol in syntax defined by the system
    ele-1: All FHIR elements must have a @value or children
    Fixed Value: vital-signs
    ... code SΣ 1..1 CodeableConcept Coded Responses from C-CDA Vital Sign Results
    Binding: Vital Sign Result Type . (extensible): Vital sign result types


    ele-1: All FHIR elements must have a @value or children
    Required Pattern: At least the following
    .... coding 1..* Coding Code defined by a terminology system
    Fixed Value: (complex)
    ..... system 1..1 uri Identity of the terminology system
    Fixed Value: http://loinc.org
    ..... code 1..1 code Symbol in syntax defined by the system
    Fixed Value: 39156-5
    ... subject SΣ 1..1 Reference(US Core Patient Profile) Who and/or what the observation is about
    ele-1: All FHIR elements must have a @value or children
    ... effective[x] SΣC 1..1 Often just a dateTime for Vital Signs
    ele-1: All FHIR elements must have a @value or children
    vs-1: if Observation.effective[x] is dateTime and has a value then that value shall be precise to the day
    .... effectiveDateTime dateTime
    ... performer SΣ 0..* Reference(US Core Practitioner Profile | US Core Organization Profile | US Core Patient Profile | PractitionerRole | US Core CareTeam Profile | US Core RelatedPerson Profile) Who is responsible for the observation
    ele-1: All FHIR elements must have a @value or children
    ... Slices for value[x] SΣC 0..1 Vital Signs Value
    Slice: Unordered, Open by type:$this
    Binding: VitalSignsUnits (extensible): Common UCUM units for recording Vital Signs.


    ele-1: All FHIR elements must have a @value or children
    .... valueQuantity Quantity
    .... value[x]:valueQuantity SΣC 0..1 Quantity Vital Signs Value
    Binding: VitalSignsUnits (extensible): Common UCUM units for recording Vital Signs.


    ele-1: All FHIR elements must have a @value or children
    ..... value SΣ 1..1 decimal Numerical value (with implicit precision)
    ele-1: All FHIR elements must have a @value or children
    ..... comparator ?!Σ 0..1 code < | <= | >= | > - how to understand the value
    Binding: QuantityComparator (required): How the Quantity should be understood and represented.


    ele-1: All FHIR elements must have a @value or children
    ..... unit SΣ 1..1 string Unit representation
    ele-1: All FHIR elements must have a @value or children
    ..... system SΣC 1..1 uri System that defines coded unit form
    ele-1: All FHIR elements must have a @value or children
    Fixed Value: http://unitsofmeasure.org
    ..... code SΣ 1..1 code Coded responses from the common UCUM units for vital signs value set.
    ele-1: All FHIR elements must have a @value or children
    Fixed Value: kg/m2
    ... dataAbsentReason SC 0..1 CodeableConcept Why the result is missing
    Binding: DataAbsentReason (extensible): Codes specifying why the result (Observation.value[x]) is missing.


    ele-1: All FHIR elements must have a @value or children
    ... component SΣC 0..* BackboneElement Component observations
    ele-1: All FHIR elements must have a @value or children
    vs-3: If there is no a value a data absent reason must be present
    .... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
    ele-1: All FHIR elements must have a @value or children
    ext-1: Must have either extensions or value[x], not both
    .... code SΣ 1..1 CodeableConcept Coded vital sign result type
    Binding: Vital Sign Result Type . (extensible): Vital sign result types


    ele-1: All FHIR elements must have a @value or children
    .... value[x] SΣC 0..1 Vital Sign Component Value
    Binding: VitalSignsUnits (extensible): Common UCUM units for recording Vital Signs.


    ele-1: All FHIR elements must have a @value or children
    ..... valueQuantity Quantity
    .... dataAbsentReason SC 0..1 CodeableConcept Why the component result is missing
    Binding: DataAbsentReason (extensible): Codes specifying why the result (Observation.value[x]) is missing.


    ele-1: All FHIR elements must have a @value or children

    doco Documentation for this format

    Terminology Bindings

    PathConformanceValueSet / CodeURI
    Observation.statusrequiredObservationStatus
    http://hl7.org/fhir/ValueSet/observation-status|4.0.1
    from the FHIR Standard
    Observation.categorypreferredObservationCategoryCodes
    http://hl7.org/fhir/ValueSet/observation-category
    from the FHIR Standard
    Observation.category:VSCatpreferredObservationCategoryCodes
    http://hl7.org/fhir/ValueSet/observation-category
    from the FHIR Standard
    Observation.codeextensiblePattern: LOINC Code 39156-5
    http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.3.88.12.80.62
    Observation.value[x]extensibleVitalSignsUnits
    http://hl7.org/fhir/ValueSet/ucum-vitals-common|4.0.1
    from the FHIR Standard
    Observation.value[x]:valueQuantityextensibleVitalSignsUnits
    http://hl7.org/fhir/ValueSet/ucum-vitals-common|4.0.1
    from the FHIR Standard
    Observation.value[x]:valueQuantity.comparatorrequiredQuantityComparator
    http://hl7.org/fhir/ValueSet/quantity-comparator|4.0.1
    from the FHIR Standard
    Observation.dataAbsentReasonextensibleDataAbsentReason
    http://hl7.org/fhir/ValueSet/data-absent-reason
    from the FHIR Standard
    Observation.component.codeextensibleVitalSignResultType .
    http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.3.88.12.80.62
    Observation.component.value[x]extensibleVitalSignsUnits
    http://hl7.org/fhir/ValueSet/ucum-vitals-common|4.0.1
    from the FHIR Standard
    Observation.component.dataAbsentReasonextensibleDataAbsentReason
    http://hl7.org/fhir/ValueSet/data-absent-reason
    from the FHIR Standard

     

    Other representations of profile: CSV, Excel, Schematron

    Notes:

    Quick Start

    Below is an overview of the required Server RESTful FHIR interactions for this profile - for example, search and read operations - when supporting the US Core interactions to access this profile's information (Profile Support + Interaction Support). Note that systems that support only US Core Profiles (Profile Only Support) are not required to support these interactions. See the US Core Server CapabilityStatement for a complete list of supported RESTful interactions for this IG.

    • See the Scopes Format section for a description of the SMART scopes syntax.
    • See the Search Syntax section for a description of the US Core search syntax.
    • See the General Requirements 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.

    US Core Scopes

    Servers providing access to vital signs data SHALL support these US Core SMART Scopes:

    • resource level scopes: <patient|user|system>/Observation.rs

    • granular scopes: <patient|user|system>/Observation.rs?category=http://terminology.hl7.org/CodeSystem/observation-category|vital-signs

    Mandatory Search Parameters:

    The following search parameters and search parameter combinations SHALL be supported:

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

      GET [base]/Observation?patient={Type/}[id]&category=http://terminology.hl7.org/CodeSystem/observation-category|vital-signs

      Example:

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

      Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and a category code = vital-signs (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 OR search on code (e.g.code={system|}[code],{system|}[code],...)

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

      Example:

      1. GET [base]/Observation?patient=1186747&code=http://loinc.org|29463-7,http://loinc.org|8302-2,http://loinc.org|39156-5

      Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and observation code(s). SHOULD support search by multiple 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 AND search on date (e.g.date=[date]&date=[date]]&...)

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

      Example:

      1. GET [base]/Observation?patient=1134281&category=http://terminology.hl7.org/CodeSystem/observation-category|vital-signs&date=ge2020-01-01T00:00:00Z

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

    Optional Search Parameters:

    The following search parameter combinations SHOULD be supported:

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

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

      Example:

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

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

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

      GET [base]/Observation?patient={Type/}[id]&category={system|}[code]&_lastUpdated={gt|lt|ge|le}[date]{&_lastUpdated={gt|lt|ge|le}[date]&...}

      Example:

      1. GET [base]/Observation?patient=1134281&category=http://terminology.hl7.org/CodeSystem/observation-category|vital-signs&_lastUpdated=ge2024-01-01T00:00:00Z

      Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and category and _lastUpdated. See the US Core General Guidance page for Searching Using lastUpdated. (how to search by reference and how to search by token and how to search by date)

    3. SHOULD support searching using the combination of the patient and code and date search parameters:
      • including optional support for 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 AND search on date (e.g.date=[date]&date=[date]]&...)

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

      Example:

      1. GET [base]/Observation?patient=1186747&code=http://loinc.org|29463-7,http://loinc.org|8302-2,http://loinc.org|39156-5&date=ge2020-01-01T00:00:00Z

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