Owning Workgroup: FHIR Infrastructure

Committee Approval Date:

Publishing Lead:

Rick Geimer

Contributing or Reviewing Work Groups:

Clinical Decision Support

FHIR Development Project Insight ID:

PSS-2200 - Getting issue details... STATUS

Scope of coverage:

The scope of this IG is limited to the CapabilityStatement resource as well as extensions and operations related to it. This IG replaces the effort previously known as [CapabilityStatement2](http://hl7.org/fhir/5.0.0-snapshot1/capabilitystatement2.html), which has since been removed from FHIR-R5, thus there is no conflict in scope with that previous effort. 

Content location:

Proposed IG Title:

FHIR Capability Discovery Implementation Guide

Proposed IG realm and code:

Universal Realm (uv)


FHIR Core version(s):

FHIR 5.0.0 or later

Maintenance Plan:

The FHIR Infrastructure WG will maintain this IG.

Short Description:

This ImplementationGuide expands the functionality of FHIR's RESTful interface with respect to system capabilities, including operations to allow fine-grained declaration of systems and to surface specific capabilities of interest to client applications without a need to retrieve an entire CapabilityStatement.

Long Description:

CapabilityStatement is the resource that is used to define both the desired capabilities of systems (via implementation guides) as well as the actual capabilities of systems (available for acquisition or in production use).  As FHIR becomes used for more different types of services, there is a need to expose in fine-grained detail exactly what a system does/is expected to do.  For example, which combinations of search parameters are legal, which languages and versions can be used in different expressions, which security headers are permitted, etc.  New implementation guides may have a need to define additional types of capabilities.

At the same time, CapabilityStatement instances for systems become increasingly large the more precise they get.  This makes them unwieldy to share.

This implementation guide defines a terminology-based extension framework on CapabilityStatement, the 'metadata' endpoint and the RESTful API allowing for fine-grained capabilities to be defined outside the FHIR core specification and also defines a mechanism for clients to query a system for specific capabilities, eliminating the need to share the entire CapabilityStatement instance.

Involved parties:


Expected implementations:

  • Grahame Grieve (e.g. tx.fhir.org)
  • Rick Geimer (Lantana)
  • Gino Canessa (Microsoft/Argonaut)
  • Richard Ettema (AEGIS)

Content sources:

The requirements will largely be drawn from what was previously known as [CapabilityStatement2](http://hl7.org/fhir/5.0.0-snapshot1/capabilitystatement2.html)

Example Scenarios:

  1. A new IG wants to define capabilities around a 'conformance' service and is able to define capabilities that can then be exposed by downstream IGs and implementations.
  2. A client app queries to determine whether a given combination of search parameters will be supported by a production FHIR interface and is told what is and isn't supported

IG Relationships:

No dependencies


First ballot: January 2024

FMG Notes