NHS FHIR integration in the UK

The strategic standard is FHIR UK Core - a FHIR R4 localisation endorsed by NHS England, with profiles spanning England, Scotland, Wales and Northern Ireland. New APIs in the NHS API catalogue are built against UK Core, with OAuth-based application access and CIS2 for user-facing authentication.

Several established programmes still run on FHIR STU3 - GP Connect is the prominent one, as is ITK3 Messaging Distribution over MESH. This split is a common source of confusion in NHS integrations - version answers that are true for one API are wrong for another, so check each API's entry in the catalogue rather than assuming.

GP Connect exposes GP practice records to other care settings - HTML views and structured data for medications and allergies, plus appointment management. It runs on FHIR STU3 through the Spine Secure Proxy, and callers authenticate system-to-system with signed JWTs describing the calling system and user context.

From an integration layer, an STU3 API is consumed the same way as R4 - the resource shapes differ, the HTTP and OAuth mechanics do not. Keeping GP Connect calls in their own services, separate from UK Core R4 services, keeps the version difference from leaking across the codebase.

One outgoing FHIR connection per NHS environment - sandbox, integration, production - each with its OAuth definition, and the services stay identical across environments. The service below reads a patient from a UK Core endpoint and lists their medication requests.

# -*- coding: utf-8 -*-

# Zato
from zato.server.service import Service

class ReadMedications(Service):
    name = 'demo.nhs.read-medications'

    def handle(self) -> 'None':

        # The connection points at a UK Core R4 endpoint
        client = self.fhir['FHIR.NHS']

        # The NHS number is the national identifier
        patient = client.resources('Patient').search(
            identifier = 'https://fhir.nhs.uk/Id/nhs-number|9000000009',
        ).first()

        # Active medication requests for that patient
        medications = client.resources('MedicationRequest').search(
            subject = f'Patient/{patient.id}',
            status = 'active',
        )

        for medication in medications.fetch():
            name = medication.get_by_path('medicationCodeableConcept.text')
            self.logger.info('Medication: %s', name)

UK hospital systems - PAS, LIMS, RIS - still emit HL7 v2 over MLLP, and integrating them with FHIR-facing services is the standard bridge pattern - an MLLP channel receives the v2 message, a Python service transforms it and the FHIR side is one save.

# -*- coding: utf-8 -*-

# Zato
from zato.server.service import Service

class PASToFHIR(Service):
    name = 'demo.nhs.pas-to-fhir'

    def handle(self) -> 'None':

        # An ADT from the PAS, parsed by the MLLP channel ..
        msg = self.request.input

        # .. the NHS number arrives in PID-3 ..
        nhs_number = msg.pid.patient_identifier_list.id_number
        family_name = msg.pid.patient_name.family_name

        # .. and becomes a UK Core identifier on the FHIR side.
        client = self.fhir['FHIR.NHS']

        patient = client.resource('Patient',
            identifier = [{
                'system': 'https://fhir.nhs.uk/Id/nhs-number',
                'value': nhs_number,
            }],
            name = [{'family': family_name}],
        )

        patient.save()