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Interoperability

What is FHIR UK Core?

Short answer

FHIR UK Core is the UK's common set of FHIR R4 profiles, extensions, value sets, code systems and concept maps. In England its development is governed by an information standard, DAPB4020, published under section 250 of the Health and Social Care Act 2012, so health and care organisations and their suppliers build FHIR interfaces in a consistent way.

Sources checked October 2026 · General information, not legal, regulatory or clinical safety advice

What UK Core is for

Base FHIR resources are deliberately general. Every country and many projects tighten them with profiles: which elements must be present, which terminology to use, which extensions are allowed. Without a national core, each supplier and each trust would profile Patient, Encounter or Observation differently and integration would start from scratch every time. NHS England says the NHS uses FHIR UK Core to make integration with APIs and services easier.

The standard behind it

NHS England publishes UK Core FHIR Release 4 – Governance (reference DAPB4020 Amd 33/2021) in the NHS Standards Directory. Its listing records:

  • Status: active; approved on 2 March 2022 and published on 11 March 2022.
  • Legal basis: an information standard under section 250 of the Health and Social Care Act 2012.
  • What it does: sets the governance for developing, maintaining and publishing UK Core, and mandates a consistent approach to developing UK Core resources across health and adult social care in England.
  • Applies to: health and care organisations in England sharing patient information between IT systems, and owners of data sets and technical standards in DHSC and its arm's length bodies.
  • Impact: health and care IT suppliers should consider updating existing FHIR assets to be in line with UK Core.
  • Dependencies: HL7 FHIR R4, SNOMED CT, the Dictionary of Medicines and Devices (dm+d), the NHS Data Model and Dictionary, and semantic versioning.

What it means for a hospital digital team

When you buy or build something with a FHIR interface, ask whether it uses UK Core profiles, and which version of the UK Core implementation guide. The Standards Directory relates the governance standard to the UK Core Implementation Guide 1.0.0 (STU1); ask which version a supplier implements and how they'll follow later ones. National FHIR APIs such as the Personal Demographics Service FHIR API are a good guide to what "NHS FHIR" looks like in practice.

What it does not mean

  • UK Core isn't a product or a server. It's a set of FHIR definitions and the governance around them.
  • It isn't FHIR R5. The governance standard names HL7 FHIR R4 as the base for its profiles, extensions, value sets, code systems and concept maps.
  • It doesn't set a conformance deadline. The listing says there is no set conformance date, but organisations in scope must work out its impact and plan for it.

Where Thalix fits

Thalix keeps clinical data as FHIR R4, and its fhir driver reads from and writes to FHIR R4 servers (read, search, create, update, transactions, $everything, subscriptions and SMART Backend Services). We don't claim UK Core profile conformance today; if a pilot needs UK Core-conformant output to another system, that belongs in the assessment and the safety case for that pilot.

Thalix is at pilot stage. Demos run on synthetic data, and a hospital deployment needs its own clinical safety case, information governance approval and security review. We don't claim any certification or assessment result the product doesn't have.

Questions people ask

Is UK Core mandatory?

The UK Core governance standard is an active information standard under section 250 of the Health and Social Care Act 2012. It mandates a consistent approach to developing UK Core resources in England, but there's no set conformance date; organisations in scope must assess its impact and plan for it.

Which FHIR version is UK Core based on?

FHIR R4. The NHS Standards Directory lists HL7 FHIR R4 as the dependency used for UK Core's profiles, extensions, value sets, code systems and concept maps.

What terminology does UK Core use?

Its listed dependencies include SNOMED CT, the Dictionary of Medicines and Devices (dm+d) and the NHS Data Model and Dictionary.

Sources

Each source below is an official page, read and checked in October 2026. Where a page and this guide differ, the official page wins.

General information only, written for hospital digital, IT, operations and clinical safety teams. It isn't legal, regulatory, information governance or clinical safety advice, and it doesn't replace your own organisation's processes or the official guidance linked above.

InteroperabilityHL7 v2 vs FHIR: what's the difference?HL7 v2 sends event messages built from segments; FHIR exchanges modular resources over REST, messages or documents. How they differ, and why hospitals run both. InteroperabilityInteroperability standards in the NHS: a map for hospital teamsFHIR and UK Core, HL7 v2, SNOMED CT, the NHS Number, PDS and the clinical safety standards: what each does and how they fit together in a hospital. InteroperabilitySMART Backend Services explained: system-to-system FHIR accessSMART Backend Services lets a server get a FHIR access token with no user present, using a registered key, a signed JWT and client credentials. InteroperabilityThe NHS Number and PDS: matching patients across hospital systemsHow the NHS Number and the Personal Demographics Service identify patients, what the national usage policy requires, and where matching goes wrong.

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