DD4C has been migrated to Delen, with effect of November 2022. A summary of how content and functionality is affected after the migration onto Delen, is provided on this page.

What is the DD4C?

The DD4C provides information (metadata) about SNOMED CT refsets and subsets. It is designed to help users to better understand the purpose and intended uses of refsets and subsets. It does not include the members that make up the refsets and subsets.

DD4C on Delen

The DD4C service provides a catalogue of existing SNOMED CT refsets and subsets that are published elsewhere (e.g., NHS England Terminology Server, Technology Reference Update Distribution (TRUD), NHS Digital SNOMED CT Browser). It includes information to aid the understanding of SNOMED CT material and provides access to this catalogue in a single location.

The aim of the service is to help support the quality of care through information being recorded once and enabling data to flow (interoperability) between systems, for the end-to-end care of patients and populations. Achieving such interoperability will enable co-ordinated, planned care, as well as more effective use of care information.

Searching DD4C

Please begin viewing the DD4C by using the 'Quick Search' below or the 'Advanced Search' by selecting the 'magnifying glass' icon or the 'Search this database' option at the bottom left hand-side of the screen.

Requesting Changes

Only read-access is available to DD4C content on Delen. If you want to add new content, modify or archive existing content, this must be made by making requests to the Terminology and Classifications Delivery Service. More details of how to request a change is provided on this page.