FHIR Release 3 (STU) Current Build
This page is part of FHIR STU 3 (v3.0.1) in it's permanent home (it will always be available at this URL). It has been superceded by R4 . For a full list of available versions, see the Directory of published versions .
FHIR Infrastructure Work Group Maturity Level : 5 Normative Ballot Standards Status : Trial Use Normative
This page has been approved as part of an ANSI standard. See the Infrastructure Package for further details.
Standards Status This element has a standards status of "Normative"

Base definition for all elements in a resource.

Control Cardinality 1..1 0..*
Defined on this element
ele-1 : Rule All FHIR elements must have a @value or children ( expression : hasValue() | or (children().count() > id.count()), xpath: @value|f:*|h:div) id.count())
Affect this element

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

Control Cardinality 0..1
Type string

May be used to represent additional information that is not part of the basic definition of the element. In order to 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 is allowed to can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

Control Cardinality 0..*
Type Extension
Alternate Names extensions; user content

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.