SNOMED CT subsets are an important resource in many implementations. They allow sets of SNOMED components to be grouped together, to support specific use cases, e.g. for data entry of diagnoses for a clinical specialty, for prioritisation of translations, and for data analytics queries. For example, in HL7 FHIR specifications, SNOMED CT value sets are specified in the terminology binding of relevant coded data elements.

Please note that:

• A SNOMED CT subset is a set of SNOMED CT components from a particular SNOMED CT edition.
• A SNOMED CT reference set is a standard format for maintaining and distributing a set of references to SNOMED CT components.
• A SNOMED CT value set is a set of valid concepts or expressions intended to constrain the permissible content for a particular use (e.g. data entry into a particular field).

An implementation requirement for SNOMED CT subsets can be satisfied by tools that create generic SNOMED CT subsets, standard RF2 reference sets, or HL7 value sets. The choice of tooling will depend on the implementation artefacts required. For example, a SNOMED CT terminology server may require a SNOMED CT RF2 reference set format.

SNOMED International Reference Set Tool

SNOMED International provides a Reference Set and Translation Tool that can be used to create and maintain SNOMED CT reference sets (see screenshot below).

The features related to reference sets include:

• Creation of extensional and intensional simple type reference sets (of SNOMED CT concepts)
• Addition of reference set members by selecting individual concepts, by uploading a flat file, or by specifying a query
• Migration of reference sets to a new versioned SNOMED CT edition
• Collaborative workflow for reference set authoring and review
• Download and publication of reference sets
• Management of reference set metadata
• Sharing of reference sets via a directory

Other Subset Tools

Other SNOMED CT subset tools are available, as listed below.

Please note that this list of subset tools is provided in alphabetical order. To request the addition or removal of a subset tool to/from this list, please submit a request via the 'Feedback' button at the bottom of this page.