UKCore Hackathon Supporting Guide

This guidance is under active development by NHS England and content may be added or updated on a regular basis.


Introduction to FHIR

FHIR is a high level framework used to build standards for passing electronic health care data between systems.

FHIR is grouped into Modules:

  • Foundation
  • Security & Privacy
  • Conformance
  • Terminology
  • Exchange
  • Administration
  • Clinical
  • Diagnostic
  • Medications
  • Workflow
  • Financial

The basic building blocks of FHIR are known as Resources to store data in a structured format. For instance, it is possible to model every patient using a single Patient Resource. These can be used separately or linked together to build a more complex system and can be stored in XML, JSON, or RDF formats. Exchanging data is usually done using RESTful APIs or FHIR messaging.

The exchange of data within a Resource is also flexible allowing only the data necessary to be transferred, reducing excess and clutter.

The FHIR website can be found here.

Introduction to UKCore

The Resources within FHIR have been left very generic on purpose so that it fits a whole range of healthcare systems. The UKCore constrains these Resources into what is known as Profiles to ensure the data collected and exchanged conform to the Legislation and Standards used within the UK healthcare.

Profiles can only restrict what is in FHIR resources, although additions can be added in the form of Extensions. There are base Extensions within FHIR that can be used to store data for the more unique cases, FHIR works on the principle that 80% of data can be modelled with Resources, the other 20% will be modelled using Extensions. The UKCore Extensions are there to store the unique data for the individual countries, for example NHS numbers.

Coded data is also standardised as far as possible to ensure it can be understood by any system receiving the data. ValueSets show what restrictions are in place for any coded data. For example, whether the data populated needs to come from dm+d or SNOMED CT, or even country specific data dictionaries, the latter being stored in what are known as CodeSystems.

UKCore currently uses the R4 sequence of FHIR.


It is expected that you conform to the UKCore by using its Implementation Guide (IG). This guide only states the differences between the UKCore and the FHIR standard, so it is necessary to use alongside the FHIR R4 guide to conform to these standards.

The latest versions of UKCore packages and Implementation Guides can be found here.


The FHIR Community chat:


FHIR Chat UK Stream

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