How does FHIR redefine data granularity compared to CDA exchanges?
It structures information around discrete, addressable "Resources".
The core innovation of FHIR regarding data structure is its move away from exchanging large, static documents, like those common in CDA implementations. Instead, FHIR structures healthcare information around discrete, separately addressable components known as "Resources." Examples include a Patient Resource, an Observation Resource, or an Encounter Resource. This resource-based approach is intrinsically aligned with the query/response model inherent in RESTful APIs. By breaking data into these granular pieces, systems can request only the specific information needed at a particular moment, enabling far more efficient and targeted data access than exchanging entire documents, which was characteristic of earlier standards.
