Release 5 Draft Ballot

This page is part of the FHIR Specification (v4.6.0: R5 Draft Ballot). The current version which supercedes this version is 5.0.0. For a full list of available versions, see the Directory of published versions . Page versions: R4B R4 R3

Extension: unit

FHIR Infrastructure Work Group

Maturity Level: 1

Informative

Use Context: Any

URL for this extension:

http://hl7.org/fhir/StructureDefinition/questionnaire-unit

Status: draft. Extension maintained by: HL7

Provides a computable unit of measure associated with numeric questions to support subsequent computation on responses. This is for use on items of type integer and decimal, and its purpose is to support converting the integer or decimal answer into a Quantity when extracting the data into a resource. If a 'display' value is provided for valueCoding of this extension and the associated question item does not have a child 'display' item with an itemControl extension of 'unit', then form fillers SHOULD take the display value of this extension and use it as as the unit display.

Comment:

The human-readable unit is conveyed as a display element. This element is for computation purposes.

Context of Use: Use on Element ID Questionnaire.item, with Context Invariant = type='integer' or type='decimal'

Summary

Name	Flags	Card.	Type	Description & Constraints
unit		0..1	Coding	URL = http://hl7.org/fhir/StructureDefinition/questionnaire-unit unit: Provides a computable unit of measure associated with numeric questions to support subsequent computation on responses. This is for use on items of type integer and decimal, and its purpose is to support converting the integer or decimal answer into a Quantity when extracting the data into a resource. If a 'display' value is provided for valueCoding of this extension and the associated question item does not have a child 'display' item with an itemControl extension of 'unit', then form fillers SHOULD take the display value of this extension and use it as as the unit display. Use on Element ID Questionnaire.item, with <a href="structuredefinition-definitions.html#StructureDefinition.contextInvariant">Context Invariant</a> = <code>type='integer' or type='decimal'</code>
Documentation for this format

Full Structure

Name	Card.	Type	Description & Constraints
extension	0..1	Extension	URL = http://hl7.org/fhir/StructureDefinition/questionnaire-unit unit: Provides a computable unit of measure associated with numeric questions to support subsequent computation on responses. This is for use on items of type integer and decimal, and its purpose is to support converting the integer or decimal answer into a Quantity when extracting the data into a resource. If a 'display' value is provided for valueCoding of this extension and the associated question item does not have a child 'display' item with an itemControl extension of 'unit', then form fillers SHOULD take the display value of this extension and use it as as the unit display. Use on Element ID Questionnaire.item, with <a href="structuredefinition-definitions.html#StructureDefinition.contextInvariant">Context Invariant</a> = <code>type='integer' or type='decimal'</code>
extension	0..0
url	1..1	uri	"http://hl7.org/fhir/StructureDefinition/questionnaire-unit"
value[x]	1..1	Coding	Value of extension
Documentation for this format

XML Template

<!-- unit -->

<extension xmlns="http://hl7.org/fhir"
     url="http://hl7.org/fhir/StructureDefinition/questionnaire-unit" >
  <!-- from Element: extension -->
 <valueCoding><!--  1..1 Coding Value of extension --></valueCoding>
</extension>

JSON Template

{ // unit
  // from Element: extension
    "extension" : [ //  sliced by value:url  in the specified order, Open ]
    "url" : "http://hl7.org/fhir/StructureDefinition/questionnaire-unit", // R! 
    "valueCoding" : { Coding } // C? R! Value of extension
  }

Summary

Name	Flags	Card.	Type	Description & Constraints
unit		0..1	Coding	URL = http://hl7.org/fhir/StructureDefinition/questionnaire-unit unit: Provides a computable unit of measure associated with numeric questions to support subsequent computation on responses. This is for use on items of type integer and decimal, and its purpose is to support converting the integer or decimal answer into a Quantity when extracting the data into a resource. If a 'display' value is provided for valueCoding of this extension and the associated question item does not have a child 'display' item with an itemControl extension of 'unit', then form fillers SHOULD take the display value of this extension and use it as as the unit display. Use on Element ID Questionnaire.item, with <a href="structuredefinition-definitions.html#StructureDefinition.contextInvariant">Context Invariant</a> = <code>type='integer' or type='decimal'</code>
Documentation for this format

Full Structure

Name	Card.	Type	Description & Constraints
extension	0..1	Extension	URL = http://hl7.org/fhir/StructureDefinition/questionnaire-unit unit: Provides a computable unit of measure associated with numeric questions to support subsequent computation on responses. This is for use on items of type integer and decimal, and its purpose is to support converting the integer or decimal answer into a Quantity when extracting the data into a resource. If a 'display' value is provided for valueCoding of this extension and the associated question item does not have a child 'display' item with an itemControl extension of 'unit', then form fillers SHOULD take the display value of this extension and use it as as the unit display. Use on Element ID Questionnaire.item, with <a href="structuredefinition-definitions.html#StructureDefinition.contextInvariant">Context Invariant</a> = <code>type='integer' or type='decimal'</code>
extension	0..0
url	1..1	uri	"http://hl7.org/fhir/StructureDefinition/questionnaire-unit"
value[x]	1..1	Coding	Value of extension
Documentation for this format

XML Template

<!-- unit -->

<extension xmlns="http://hl7.org/fhir"
     url="http://hl7.org/fhir/StructureDefinition/questionnaire-unit" >
  <!-- from Element: extension -->
 <valueCoding><!--  1..1 Coding Value of extension --></valueCoding>
</extension>

JSON Template

{ // unit
  // from Element: extension
    "extension" : [ //  sliced by value:url  in the specified order, Open ]
    "url" : "http://hl7.org/fhir/StructureDefinition/questionnaire-unit", // R! 
    "valueCoding" : { Coding } // C? R! Value of extension
  }

Constraints

ele-1: All FHIR elements must have a @value or children (xpath: @value|f:*|h:div)
ext-1: Must have either extensions or value[x], not both (xpath: exists(f:extension)!=exists(f:*[starts-with(local-name(.), 'value')]))
ele-1: On Extension.extension: All FHIR elements must have a @value or children (xpath on Extension.extension: @value|f:*|h:div)
ext-1: On Extension.extension: Must have either extensions or value[x], not both (xpath on Extension.extension: exists(f:extension)!=exists(f:*[starts-with(local-name(.), "value")]))
ele-1: On Extension.value[x]: All FHIR elements must have a @value or children (xpath on Extension.value[x]: @value|f:*|h:div)