US Core Implementation Guide
4.2.0 - CI Build

US Core Implementation Guide, published by HL7 International - Cross-Group Projects. This is not an authorized publication; it is the continuous build for version 4.2.0). This version is based on the current content of and changes regularly. See the Directory of published versions

Profiles and Extensions


The following Profiles and have been defined for this implementation guide.


The following Extensions have been defined as part of the US Core implementation Guide. A registry of standard extensions can be found in the FHIR specification and additional extensions may be registered on the HL7 FHIR registry at