Current Version - Under Revision
Read Codes and Clinical Terms Version 3 codes are present in SNOMED CT in the 900000000000497000 |CTV3 simple map reference set| which links the old alphanumeric codes to the SNOMED CT concept identifiers. For further information see the specification of Simple map reference sets .
The 900000000000497000 |CTV3 simple map reference set| can be used either to allow recognition of legacy data by SNOMED CT retrieval tools or to enable mapping of the codes and storage of the appropriate Concept Identifier .
Attention: Organizations based in the UK that are planning to migrate from NHS Clinical Terms Version 3 or earlier versions of the Read Codes are advised to review the documentation and mapping tables published by the UK NHS. These resources support more sophisticated mapping based on use of terms and patterns of use that meet UK requirements. Separate advisory documents and tables for each of the Read Code versions are available as part of the NHS Terminology Reference Data Update Distribution Service (TRUD) https://www.uktcregistration.nss.cfh.nhs.uk/trud/. These materials are updated with each SNOMED CT UK Extension Release .
1 A "Legacy code system" is code system used prior to implementation of SNOMED CT.[