HL7 FHIR — Fast Healthcare Interoperability Resources
Overview
HL7 FHIR (Fast Healthcare Interoperability Resources) is the modern standard for electronic health data exchange, developed by HL7 International. Development began in 2011 and the first published specification (DSTU1) was released in January 2014. FHIR uses RESTful APIs, JSON/XML/Turtle serialisation, and a modular resource model to enable systems to exchange health data in a standardised, machine-readable way. It is designated by the EHDS as the interoperability standard for the exchange of European health records (EHR), mandated by the US ONC 21st Century Cures Act, and required by national health IT agencies in France (ANS), the UK (NHS England), and Australia (ADHA).
Resource Model
FHIR organises all health information into Resources, discrete units of clinical information each with a defined structure, mandatory and optional fields, and a REST API endpoint. R4 defines over 140 resource types; R5 adds further coverage. Key resources relevant to neuroscience research: SNOMED CT and ICD-10 are used to code diagnoses in the Condition resource; LOINC codes lab results and cognitive assessments in the Observation resource; CCAM codes procedures in French deployments; DICOM imaging studies are linked via the ImagingStudy resource using WADO-RS endpoints; ResearchStudy and ResearchSubject carry clinical trial metadata with alignment to CDISC; the Consent resource records patient consent, relevant for EHDS secondary use scenarios; and DocumentReference links to unstructured documents such as discharge summaries.
Versioning
FHIR has gone through several major versions. DSTU2 and STU3 are widely deployed legacy versions. R4 (2019) is the current stable international baseline used by the EHDS, NHS, and ANS. R4B (2022) is a minor update adding medication knowledge and clinical reasoning resources. R5 (2023) is the latest version with improved data modelling, subscriptions, and cross-version mapping. Most production deployments in France use R4.
SMART on FHIR
SMART on FHIR (Substitutable Medical Applications, Reusable Technologies) is the OAuth2/OpenID Connect-based authorisation framework built on top of FHIR. It enables third-party applications to securely access patient data from FHIR servers with patient or clinician consent, and is the standard for EHR app ecosystems (Epic, Cerner, Oracle Health) and clinical research portal applications.
FHIR and OMOP
FHIR and OMOP CDM serve complementary roles. FHIR is the operational and clinical data exchange standard enabling real-time API access, while OMOP CDM is the analytical standard for retrospective research, populated by periodically copying data out of EHR systems and reshaping it into the OMOP tables. The same conversion process turns FHIR resources into OMOP tables (OHDSI provides FHIR-to-OMOP mapping tools). The EHDS designates FHIR for primary use EHR exchange and aligns with OMOP CDM for secondary use data standardisation.
Connections
- endorsedBy: EHDS
- relatedTo: ANS (ANS governs French FHIR implementation guides and national interoperability profiles)
- relatedTo: OMOP CDM (conversion pipelines move data between FHIR’s operational records and OMOP’s analytical tables)
- relatedTo: openEHR (bidirectional mapping work for clinical data interoperability)
- relatedTo: DICOM (ImagingStudy resource links FHIR records to DICOM imaging studies via WADO-RS)
- relatedTo: CDISC (ResearchStudy resource alignment for clinical trial data exchange)
- implements: SNOMED CT
- implements: LOINC
- implements: ICD-10
Resources
- https://hl7.org/fhir/ (FHIR R4 specification)
- https://hl7.org/fhir/R5/ (FHIR R5 specification)
- https://smarthealthit.org (SMART on FHIR)
- https://esante.gouv.fr/ans-nationale/convergences-fhir (ANS French FHIR IGs)
- https://hl7vulcan.org/projects/fhir-to-omop/ (HL7 Vulcan FHIR-to-OMOP project)