US Core BMI Profile - US Core Implementation Guide v7.0.0-ballot

US Core Implementation Guide
7.0.0-ballot - Ballot United States of America flag

This page is part of the US Core (v7.0.0-ballot: STU7 Ballot 1) based on FHIR (HL7® FHIR® Standard) R4. The current version which supersedes this version is 6.1.0. For a full list of available versions, 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: 7.0.0-ballot
Standards status: Trial-use	Maturity Level: 3	Computable Name: USCoreBMIProfile
Copyright/Legal: Used by permission of HL7 International, all rights reserved Creative Commons License

To promote interoperability and adoption through common implementation, this profile sets minimum expectations for the Observation resource to record, search, and fetch Body Mass Index (BMI) observations with a standard LOINC code and UCUM units of measure. It is based on the US Core Vital Signs Profile and identifies which additional core elements, extensions, vocabularies, and value sets SHALL be present and constrains the way the elements are used when using the profile. It provides the floor for standards development for specific use cases.

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:

a patient
a fixed code for body mass index (BMI)

Each Observation Must Support:

a result value

Profile Specific Implementation Guidance:

- Note that this profile also conforms to the base FHIR Vital Signs Profile.

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. Several of these are provided in the FHIR core specification vital signs table.
*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:

Examples for this Resource Profile: Observation/bmi

Formal Views of Profile Content

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

Differential Table
Key Elements Table
Snapshot Table
Statistics/References
All

This structure is derived from USCoreVitalSignsProfile

Name	Flags	Card.	Type	Description & Constraints
Observation		0..*	USCoreVitalSignsProfile	US Core Body Mass Index (BMI) Profile
code	S	1..1	CodeableConcept	Coded Responses from C-CDA Vital Sign Results 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
valueQuantity	S	0..1	Quantity S	Vital Signs Value
value	S	1..1	decimal	Numerical value (with implicit precision)
unit	S	1..1	string	Unit representation
system	S	1..1	uri	System that defines coded unit form Fixed Value: http://unitsofmeasure.org
code	S	1..1	code	Coded responses from the common UCUM units for vital signs value set. Fixed Value: kg/m2
Documentation for this format

Name	Flags	Card.	Type	Description & Constraints
Observation	C	0..*	USCoreVitalSignsProfile	US Core Body Mass Index (BMI) Profile
implicitRules	?!Σ	0..1	uri	A set of rules under which this content was created
modifierExtension	?!	0..*	Extension	Extensions that cannot be ignored
status	?!SΣ	1..1	code	registered \| preliminary \| final \| amended + Binding: ObservationStatus (required)
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.
category:VSCat	S	1..1	CodeableConcept	Classification of type of observation Binding: ObservationCategoryCodes (preferred): Codes for high level observation categories.
coding	SΣ	1..*	Coding	Code defined by a terminology system
system	SΣ	1..1	uri	Identity of the terminology system Fixed Value: http://terminology.hl7.org/CodeSystem/observation-category
code	SΣ	1..1	code	Symbol in syntax defined by the system Fixed Value: vital-signs
code	SΣ	1..1	CodeableConcept	Coded Responses from C-CDA Vital Sign Results Binding: US Core Vital Signs ValueSet (extensible): The vital sign codes from the base FHIR and US Core Vital Signs. 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
effective[x]	SΣC	1..1		Often just a dateTime for Vital Signs
effectiveDateTime			dateTime
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.
valueQuantity			Quantity
value[x]:valueQuantity	SΣC	0..1	Quantity	Vital Signs Value Binding: VitalSignsUnits (extensible): Common UCUM units for recording Vital Signs.
value	SΣ	1..1	decimal	Numerical value (with implicit precision)
comparator	?!Σ	0..1	code	< \| <= \| >= \| > - how to understand the value Binding: QuantityComparator (required): How the Quantity should be understood and represented.
unit	SΣ	1..1	string	Unit representation
system	SΣC	1..1	uri	System that defines coded unit form Fixed Value: http://unitsofmeasure.org
code	SΣ	1..1	code	Coded responses from the common UCUM units for vital signs value set. 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.
component	SΣC	0..*	BackboneElement	Component observations
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
code	SΣ	1..1	CodeableConcept	Type of component observation (code / type) Binding: US Core Vital Signs ValueSet (extensible): The vital sign codes from the base FHIR and US Core Vital Signs.
value[x]	SΣC	0..1		Vital Sign Component Value Binding: VitalSignsUnits (extensible): Common UCUM units for recording Vital Signs.
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.
Documentation for this format

Terminology Bindings

Path	Conformance	ValueSet / Code
Observation.status	required	ObservationStatus
Observation.category	preferred	ObservationCategoryCodes
Observation.category:VSCat	preferred	ObservationCategoryCodes
Observation.code	extensible	Pattern: LOINC code 39156-5
Observation.value[x]	extensible	VitalSignsUnits
Observation.value[x]:valueQuantity	extensible	VitalSignsUnits
Observation.value[x]:valueQuantity.comparator	required	QuantityComparator
Observation.dataAbsentReason	extensible	DataAbsentReason
Observation.component.code	extensible	UsCoreVitalSigns
Observation.component.value[x]	extensible	VitalSignsUnits
Observation.component.dataAbsentReason	extensible	DataAbsentReason

Constraints

Id	Grade	Path(s)	Details	Requirements
dom-2	error	Observation	If the resource is contained in another resource, it SHALL NOT contain nested Resources : contained.contained.empty()
dom-3	error	Observation	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	error	Observation	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	error	Observation	If a resource is contained in another resource, it SHALL NOT have a security label : contained.meta.security.empty()
dom-6	best practice	Observation	A resource should have narrative for robust management : text.`div`.exists()
ele-1	error	ALL elements	All FHIR elements must have a @value or children : hasValue() or (children().count() > id.count())
ext-1	error	ALL extensions	Must have either extensions or value[x], not both : extension.exists() != value.exists()
obs-6	error	Observation	dataAbsentReason SHALL only be present if Observation.value[x] is not present : dataAbsentReason.empty() or value.empty()
obs-7	error	Observation	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.intersect(%resource.code.coding).exists()).empty()
vs-1	error	Observation.effective[x]	if Observation.effective[x] is dateTime and has a value then that value shall be precise to the day : $this is dateTime implies $this.toString().length() >= 10
vs-2	error	Observation	If there is no component or hasMember element then either a value[x] or a data absent reason must be present. : (component.empty() and hasMember.empty()) implies (dataAbsentReason.exists() or value.exists())
vs-3	error	Observation.component	If there is no a value a data absent reason must be present : value.exists() or dataAbsentReason.exists()