This section documents the approach used by the UK Core Development team to produce and maintain the UK Core Implementation Guides and the UK Core FHIR assets. It will be updated and matured in line with decisions taken during the Clinical and Technical Assurance process. This documentation is aimed at the technical reader and is included as reference material. The approach is based on the design principles.
The UK Core conforms to the HL7 FHIR® specification (Release 4) and its assets are profiles of the corresponding base HL7 FHIR resources.
Further information about conformance in FHIR is available.
FHIR assets must not be England specific and must be capable of representing the requirements of each UK nation identified during collaboration.
If there is a draft or active UKCore version of a Resource then this Profile SHALL be used as the reference. If there is no UKCore version available then the reference SHALL be the HL7 Resource version.
FHIR Resources, along with ValueSets, CodeSystems and ConceptMaps use the American-English spelling, for example Organization. The UKCore approach is to use American-English for any Profile, Extension, ValueSet, CodeSystem, and ConceptMap names, and when directly referring to the names within the Implementation Guide, otherwise using the British-English for all other aspects.
There is a UK Core requirement to develop extensions based on any equivalent CareConnect STU3 extensions. The exception to this is where an extension is no longer needed because either
Extension will be constrained (hard coded) into profiles to profiles after agreement during Clinical and Technical assurance.
The Implementation Guide for the UK Core will include an Extension Library page, which will list extensions and their corresponding UK Core profiles. There is no requirement to profile HL7 extensions locally. Where a HL7 extension is identified as in scope, a link to it will be added on the Extension Library page under HL7 Common Extensions.
Read more about FHIR Extensions and Extension Design.
Read more about FHIR resource cardinalities.
Read more about Slicing in FHIR.
Read more about "Must Support" in FHIR.
The UKCore ValueSet binding strength SHOULD be decided as part of the Clinical and Technical Assurance, but the general philosophy is as the following:
Read more about ValueSets and ValueSet bindings in FHIR.
All FHIR assets SHALL be validated before being publicly available. See Validation of Implementations for more details.
Constraints allow for validation against more complex calculations, giving either a warning or error if the criteria has not been met. All constraints SHALL have:
Where the severity is a warning, the Human Description will say SHOULD, where the severity is error, it will say SHALL.
Warning constraints that have been inherited within a derived profile may be inhibited using the suppress
element only if it is deemed that the warning is incorrect for this profile.
Note: At this time constraints contained within derived profiles cannot be validated by the GitHub Validator, only by swagger once a package has been created containing the derived profile. Constraints can be tested beforehand using the Simplifer FHIRPath Playground, although caution is to be used as this only validates the FHIRPath on the StructureDefinition element.
More information can be found within the Conformance Rules and the Element Definition.