Subsets support user interface development through the organisation of clinical display, creation of menus and pick-lists, translation to alternative languages and dialects or support of knowledge structures.

Subsets may be created as value sets for messaging or data entry or to provide pre-coordinated SNOMED CT concepts for certain constrained use, or can inter-relate with qualifier value tables appropriate to the concept types.

Subsets have a purpose and usually represent groups of concepts (e.g. specific clinical domain) or other content which share specified characteristics.

Different types of subsets are used to represent:

• Language and dialect variants
• Descriptions or concepts for particular realms or specialties
• Suitability of particular concepts for use in a particular context in a record
• Structure and ordering of hierarchies displaying concepts for user navigation

We maintain a Subset Register which has an overview of all the national subsets provided as part of the SNOMED CT release and to also allow those who are happy to share their locally developed subsets with others across the NHS. The register allows you to enter details of any subsets you have locally (not all details are required) and provide your own contact details so others can get in touch.

To view the content of the subsets currently released by the UKTC, you can install the NHS eViewer application along with eVersions of the subsets. The eViewer is located in the Terminology Tools area in UKTC Terminology Centre on the TRUD website. Please see the 'Getting Started' guide that is provided as part of the download.

Note. If you wish to use any of these subsets please download the formal UK release of the SNOMED CT subsets from TRUD to get the full data format.