FHIR Implementation Guides (IGs)¶ FHIR IGs: Introduction Why do IGs exist? Why doesn’t FHIR cover everything? IGs versus the ImplementationGuide resource IG Versioning StructureDefinition Resource FHIRPath Example FHIR IGs FHIR IGs: Profiles Changing the Cardinality Restricting a Choice Element Fixed Values and Bindings Flagging a Data Element Slicing Invariants (or Constraints) Formal Views of Profile Content Examples US Core Patient US Core Laboratory Result Observation Extensions FHIR IGs: Terminology CodeSystems ValueSets Instances Example Instances