There are processes for making decisions about adding or changing content in SNOMED CT.

Change requests

All change requests, whether for new content or for change to existing content, go through a request submission approval process. It involves review by authors to determine that there is:

  • International applicability
  • Compliance with Understandable, Reproducible, Useful (URU) principles
  • No duplication with existing content
  • No link to existing larger projects, as detailed in a Content Tracker document
  • No conflict with existing collaboration agreements (e.g. Logical Observation Identifiers Names and Codes (LOINC) agreement)

Legacy concepts

Legacy concepts, i.e. concepts not in the current draft/work-in-progress version of SNOMED CT, may not follow current guidelines. Requests based on legacy concepts are unacceptable.

Appeals, deferrals, and resolution


Requests that are rejected may be appealed by the submitter.


Requests may be deferred for a number of reasons including questions about:

  • How to model the concept; which attributes may be used
  • Concept meaning
  • Literature reference missing or inadequate
  • Use case unclear
  • Size of required change (attached to a Content Tracker)


Resolution of deferrals may result in a decision delay requiring:

  • A larger project or work item or
  • Referral, internally, to other groups for decision. This depends on the complexity of the request and understanding of the wider impact.


Results of adjudication are received by email from the Content Request System (CRS). Simpler issues can be resolved expeditiously (e.g. by a ruling from the Chief Terminologist).

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