FHIR Extensions Pack
5.3.0 - May 2026 International flag

This page is part of the FHIR Core Extensions Registry (v5.3.0: Release 5.3) based on FHIR (HL7® FHIR® Standard) v5.0.0. This is the current published version. For a full list of available versions, see the Directory of published versions

Extension: Expression Coding

Official URL: http://hl7.org/fhir/StructureDefinition/expression-coding Version: 5.3.0
Standards status: Draft Maturity Level: 1 Computable Name: ExpressionCoding

A code that defines the meaning of the result of the expression (and that may apply to the specific means of calculating the result)

This is an draft extension definition; the committee is seeking implementation feedback, and the definition or contents of the extension may change in future versions

Context of Use

This extension may be used on the following element(s)

Usage info

Usages:

  • This Extension is not used by any profiles in this Implementation Guide

You can also check for usages in the FHIR IG Statistics

Changes since version 5.2.0:

  • New Content

    • Formal Views of Extension Content

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

    This structure is derived from Extension

    Summary

    Simple Extension with the type Coding: A code that defines the meaning of the result of the expression (and that may apply to the specific means of calculating the result)

    Maturity: 1

    This structure is derived from Extension

    NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
    .. Extension 0..* Extension What code describes the meaning of the result (e.g. a LOINC code for number of beds)
    ... url 1..1 uri "http://hl7.org/fhir/StructureDefinition/expression-coding"
    ... value[x] 1..1 Coding Value of extension
    Binding Description: (example): LOINC codes

    doco Documentation for this format
    NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
    .. Extension 0..* Extension What code describes the meaning of the result (e.g. a LOINC code for number of beds)
    ... id 0..1 id Unique id for inter-element referencing
    ... extension 0..* Extension Additional content defined by implementations
    Slice: Unordered, Open by value:url
    ... url 1..1 uri "http://hl7.org/fhir/StructureDefinition/expression-coding"

    doco Documentation for this format

    This structure is derived from Extension

    Summary

    Simple Extension with the type Coding: A code that defines the meaning of the result of the expression (and that may apply to the specific means of calculating the result)

    Maturity: 1

    Differential View

    This structure is derived from Extension

    NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
    .. Extension 0..* Extension What code describes the meaning of the result (e.g. a LOINC code for number of beds)
    ... url 1..1 uri "http://hl7.org/fhir/StructureDefinition/expression-coding"
    ... value[x] 1..1 Coding Value of extension
    Binding Description: (example): LOINC codes

    doco Documentation for this format

    Snapshot View

    NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
    .. Extension 0..* Extension What code describes the meaning of the result (e.g. a LOINC code for number of beds)
    ... id 0..1 id Unique id for inter-element referencing
    ... extension 0..* Extension Additional content defined by implementations
    Slice: Unordered, Open by value:url
    ... url 1..1 uri "http://hl7.org/fhir/StructureDefinition/expression-coding"

    doco Documentation for this format

     

    Other representations of profile: CSV, Excel, Schematron

    Terminology Bindings

    Path Status Usage ValueSet Version Source
    Extension.value[x] Base example Not State Unknown

    Constraints

    Id Grade Path(s) Description Expression
    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()

    R4B

    The extension is unchanged in R4B

    R4

    The extension is unchanged in R4

    R3

    The extension is unchanged in R3

    Search Parameters for this Extension

    (none found)