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FHIR Reference

Nexus IG 1.25.1 · draft · FHIR R4 (4.0.1) · canonical https://fhir.apps.health

The specification itself: every profile, extension, value set and code system this IG guarantees, with conforming examples. For how to WORK with it — tutorials, patterns, feature designs, contribution — see the Handbook.

  • Artifacts — the full index of profiles, extensions and terminology
  • CQL — writing clinical criteria against this specification: the model, the primary code path, and what a criteria library declares about the data it reads
  • Machine consumption — validators and tooling read the FHIR NPM package, not this website. The package, its id and the release list are on IG metadata.

How to read a profile page

Every profile page is one resource seen through tabs:

  • Overview — the narrative, plus terminology bindings and invariants
  • Elements — the element tables at three zoom levels: - Differential — only what the profile constrains beyond base R4; anything unlisted is unchanged - Key elements — the working view: must-support, required, modifiers, slices - Snapshot — the full effective definition
  • Examples — conforming instances (also nested under each resource in the sidebar). Example JSON is hyperlinked: references to other examples and canonical URLs of IG artifacts are clickable, so instances browse as a graph
  • FSH — the authored source of truth
  • Salient fields — the profile's synthesized-accessor contract
  • TypedFhir API — the generated accessor reference, per language port

Flags in element tables: S = must-support · ?! = modifier — hover for the meaning, click for the R4 definition.