This is the list of ValueSets and CodeSystems defined for use within the UK Core.
Other ValueSets are useable if the binding strength is defined as extensible. For more information see
HL7 FHIR - Binding Strengths.
The UK Core ValueSets have been assigned a maturity level similar to the maturity levels described in the FHIR standard. This is intended to indicate how stable the ValueSet is deemed to be, this is in addition to the publication status of the ValueSet HL7 FHIR statuses of draft, active, retired and unknown.
Important note regarding use of SNOMED CT and the binding strength of extensible.
The FHIR standard states the following for extensible: To be conformant, codes in this element SHALL be from the specified value set if any of the codes within the value set can apply to the concept being communicated. If there is no applicable concept in value set (based on human review), an alternate concept (either system/code pair, or text) may be used instead. The important part of this statement is the human review (see 3 below).
For most clinical data exchanges SNOMED CT is the preferred CodeSystem to use, however there are many use cases where this is not possible. For example:
- The data is historical and previously coded in another terminology such as READ
- The sending system does not support SNOMED CT
- The SNOMED CT Ref set has tens of thousands of members which makes encoding in SNOMED CT impractical or not possible based on human review
Therefore the guidance for UK Core is: The binding of extensible should be interpreted as encode in SNOMED CT if possible but it is allowable to encode using alternative coding systems or use text.
Important Note:
Where then is a derived Implementation Guide this may override this guidance and enforce SNOMED CT encoding.
Important note regarding the use of the "preferred" binding strength for UK Core ValueSets containing CodeSystems specific to individual UK countries.
Where different countries within the UK use different sets of concepts for the same data item (see list of ValueSets below where this is the case), currently the default approach to supporting this data within the UK Core is to create a CodeSystem for each individual country where requirements have been confirmed, and incorporate each such CodeSystem within a ValueSet that is then bound into the profile or extension supporting the data item (referred to as the "individual country specific CodeSystem" approach).
In most cases where this approach is taken, for some of the concepts the ValueSet does contain more than one entry for the same concept. For this reason, the use of the "extensible" binding strength is deemed to be inappropriate and "preferred" is determined to be the most suitable binding strength to use instead.
Work has begun to look at whether an alternative way of expressing UK Core ValueSets would be preferable where similar and potentially overlapping sets of concepts are used for the same data within the UK. The alternative approach being considered is to create a single CodeSystem which amalgamates all the different concepts from UK countries where requirements can be confirmed, creating a UK Core code for each such concept, and then using concept maps to map from the UK Core CodeSystem to a CodeSystem from each country where concepts have been taken from (referred to as the "superset of concepts" approach).
It is anticipated that a meeting will be held in early 2022 for interested parties to look at some examples comparing the "individual country specific CodeSystem" and "superset of concepts" approaches, with a view to determining the best approach for the UK Core going forward and what should happen with existing UK Core ValueSets where the "individual country specific CodeSystem" has already been utilised if the "superset of concepts" is deemed to be the better approach.
UK Core ValueSets where this issue arises:
- UKCore-AdmissionMethod
- UKCore-DischargeDestination
- UKCore-DischargeMethod
- UKCore-EmergencyCareDischargeStatus
- UKCore-EncounterLocationType
- UKCore-EthnicCategory
- UKCore-LegalStatusClassification
- UKCore-OutcomeOfAttendance
- UKCore-SourceOfAdmission