Release 4

This page is part of the FHIR Specification (v4.0.1: R4 - Mixed Normative and STU) in it's permanent home (it will always be available at this URL). 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 R2

FHIR Infrastructure Work GroupMaturity Level: NormativeStandards Status: Normative
This page has been approved as part of an ANSI standard. See the Infrastructure Package for further details.
Element
Standards StatusThis element has a standards status of "Normative"
Definition

Base definition for all elements in a resource.

Cardinality0..*
Invariants
Defined on this element
ele-1Rule All FHIR elements must have a @value or childrenhasValue() or (children().count() > id.count())
Affect this element
Element.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

Cardinality0..1
Typestring
Element.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Cardinality0..*
TypeExtension
Alternate Namesextensions; user content
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.