FHIR Exchange Paradigms

FHIR is an API contract that supports semantically meaningful clinical data exchange. To do this, it makes certain basic assumptions about how that data is exchanged, and provides paradigms for how the process should flow.

RESTful APIs

The most basic paradigm for accessing information from the CDR as a FHIR store is by performing a RESTful API call. FHIR is capable of supporting all REST operations, but adds certain additional constraints to support semantic interoperability.

For more details, see the HL7 International guide to FHIR RESTful API calls.

Messaging

A more advanced paradigm for data exchange is that of FHIR Messaging. This mirrors traditional data exchange using the older HL7 v2 Messaging Specification historically in use in the NHS in Wales. In order to use FHIR Messaging, additional constraints and variants are added to the API call in structured patterns.

Many of the use cases in this implementation guide set out the requirements for these FHIR Messaging operations.

For more details, see the HL7 International guide to Messaging using FHIR.

Other Paradigms

There are other paradigms which are much more rarely used in the CDR, but which are supported by FHIR. These include Document, Service, and Persistence approaches. More details can be found in the HL7 International FHIR Exchange Module.