Release of SNOMED CT

Development, Quality Assurance and Release

SNOMED CT is continuously updated to meet the needs of users around the world. Revisions to the international version of SNOMED CT are released twice a year. Each release includes updates to:

  • Core terminology components (concepts, descriptions, and relationships)
  • Derivatives that support implementation and use of SNOMED CT (reference sets, which represent subsets, cross maps to classifications and coding schemes and additional metadata).
  • Documentation (including guidelines for users, implementers and content editors).

These updates are driven by user requirements based on priorities set by the IHTSDO taking account of input from advisory bodies and guidance from the Content Committee. Typical updates include refinements to descriptions, enhancement of concept definitions and addition of new concepts. Prior to release, the SNOMED CT content undergoes a clinical and technical quality assurance process. The final stage of this review is the release of a preliminary version to IHTSDO Members for broader review before the general release is distributed to Affiliate Licensees.

Improvements to SNOMED CT

Just as our knowledge about health and health care is constantly evolving, so too are terminologies in this domain. As mentioned, the number of concepts in SNOMED CT is growing. A continuous "cleaning up" process also takes place; from 2002 to 2008 approximately 20,000 concepts were deactivated because they were duplicates, outdated, ambiguous, etc. The quality of the descriptions is also improving. For example, more concepts now have sufficient logic definitions – particularly those in the disorders and procedures hierarchies. 

You can assist your colleagues around the world in the ongoing development and maintenance of SNOMED CT by becoming a member of IHTSDO's Working Groups and Special Interest Groups; by participating in discussions on the Collaborative Space and at face-to-face meetings; or by submitting requests for specific additions or changes to the standard. We also encourage you to share your experiences of using the standard through the Members Forum, the Affiliate Forum, and at local forums and events organized by IHTSDO's members.

IHTSDO®, SNOMED® and SNOMED CT® are registered trademarks of the International Health Terminology Standards Development Organisation.