SNOMED Documentation Search

 Other Documents
Skip to end of metadata
Go to start of metadata

Current Version - Under Revision

Migration from SNOMED RT poses very few significant issues, since many features of the design of SNOMED CT including the use of SCTIDs were incorporated into SNOMED RT.

Thus transition to SNOMED CT for users of SNOMED RT is relatively straightforward because the Concept Identifiers in SNOMED RT are the same as the uses in SNOMED CT.

In some cases, during or after the merger of SNOMED RT and NHS Clinical Terms Version 3 some concept in SNOMED RT were found to be ambiguous or duplicated. Even in these cases the concepts with original identifier are still present in the SNOMED CT Concepts Table but have been inactivated.  Records in the Concept Inactivation Reference Set indicate the reason for inactivation and records in the appropriate Historical Association Reference Set can be used to locate the appropriate active concept identifier. 

For information about historical reference sets please see the following:

These Associations can be used either to allow concepts recorded using these identifiers to be recognized by retrieval tools or to enable mapping of the stored information to the appropriate active concepts.

If any stored Concept Identifier of an Inactive Concept is mapped to an active Concept Identifier using these Associations it is strongly recommended that the original Concept Identifier is also retained. This enables future improvements or corrections of such mappings if revised Associations are present in a future release of SNOMED CT .

In addition, SNOMED RT contained both generic and brand name drugs for the US. A decision was made during the merger process to not retire these concepts using the extension mechanisms, but to place these components directly in the US Drug Extension . Therefore to access all SNOMED RT components you will need to use the US Drug Extension in addition to the SNOMED CT International Release .

Like SNOMED CT , SNOMED RT also contains the appropriate legacy SNOMEDID from SNOMED International .