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What is an Implementation Guide?
An Implementation Guide (IG) bundles profiles, value sets, code systems, examples, narrative documentation, and conformance rules into a single publishable specification. An IG defines what a system must implement to be compliant with a particular use case or regulation.
What an IG contains
- Profiles: StructureDefinitions constraining base resources
- ValueSets: Curated sets of codes from one or more CodeSystems
- CodeSystems: Custom code lists not covered by SNOMED/LOINC
- Examples: Sample resources demonstrating correct usage
- CapabilityStatements: What servers/clients implementing this IG must support
- Narrative pages: Human-readable documentation and guidance
Major IGs
International Patient Summary (IPS) — minimal patient summary for cross-border use. Basis for EHDS.
US Core — US national baseline, mandated by ONC 21st Century Cures Act. All US payers must expose FHIR APIs compliant with US Core.
EHDS EHRxF — European Health Data Space exchange format. Under development by the EU. Mandates cross-border patient summaries, ePrescriptions, and lab results.
SMART on FHIR — authorization framework IG. Defines how apps connect to FHIR servers using OAuth2.