4.5.4. Terminology maintenance and distribution

SNOMED CT must be distributed in a format that is readily usable by application developers. This format must be fully specified and must not change from release to release.

SNOMED CT may also be distributed in a form that can be used directly with associated software, such as a browser.

The meaning of a code is persistent. It must not be changed or deleted by updates. However, a code may be marked as retired where its meaning is found to be ambiguous, redundant or otherwise incorrect.

Changes to the association between a term and a code must not result in a change or deletion of that description. Instead the description must be marked as retired and a new corrected description must be created.

All changes to SNOMED CT components are tracked and details of this changes are provided in history files.

The information provided includes details of creation of new components and changes to the status of components. When a component is made inactive, relationships or references are provided to indicate the active component that replaces or may be equivalent to the inactivated component.