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.