Release 4B

This page is part of the FHIR Specification (v4.3.0: R4B - STU). This is a downloaded version of the specification. For a full list of available versions, see the Directory of published versions

2.5.3 Extension - Detailed Descriptions

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.
Extension
Standards StatusThis element has a standards status of "Normative"
Definition

Optional Extension Element - found in all resources.

Cardinality0..*
TypeElement
Requirements

The ability to add extensions in a structured way is what keeps FHIR resources simple.

Invariants
Defined on this element
ext-1Rule Must have either extensions or value[x], not bothextension.exists() != value.exists()
Extension.url
Definition

Source of the definition for the extension code - a logical name or a URL.

Cardinality1..1
Typeuri
Comments

The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

Extension.value[x]
Definition

Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

Cardinality0..1
Type*
[x] NoteSee Choice of Data Types for further information about how to use [x]