The International Edition of SNOMED CT distributes a set of reference sets that record the reason that each inactive component was inactivated. These are referred to as "historical association" reference sets (see 4.2.3 Historical Association Reference Sets for more details). There is one historical association reference set for each type of historical association as shown in the table below.
Association reference set
|t||900000000000523009 | POSSIBLY EQUIVALENT TO association reference set ||
Applies to a that is ambiguous. The targetComponent is an active that represents one of the possible meanings of the inactive . Multiple rows are used to refer to each of the possible meanings of the ambiguous
|t||900000000000524003 | MOVED TO association reference set ||
Applies to a that has been moved to (or are pending a move to) another namespace. The targetComponent identifies the target namespace (not the new ).
|t||900000000000525002 | MOVED FROM association reference set ||
Applies to a that has been moved to this namespace from another namespace. The targetComponent identifies the original in its previous namespace.
|t||900000000000526001 | REPLACED BY association reference set ||
Applies to an erroneous, obsolete and other
for which there is a single active replacement. The targetComponent identifies the active that replaces this
|t||900000000000527005 | SAME AS association reference set ||
Applies to a that is a duplicate. The targetComponent identifies the active that this duplicates.
|t||900000000000528000 | WAS A association reference set ||
Links an inactive classification such as "not otherwise specified" or "otherwise specified" with the active that was formerly its most proximal supertype.
|t||900000000000529008 | SIMILAR TO association reference set |||(not used currently)|
|t||900000000000530003 | ALTERNATIVE association reference set ||
Links an inactive classification derived from ICD-9 Chapter XVI "Symptoms signs and ill-defined conditions" with the most similar active
|t||900000000000531004 | REFERS TO concept association reference set ||
Applies to an inactive which is inappropriate to the it is directly linked to but instead should refer to the referenced by the targetComponent.
The following table holds example entries for the
|t||900000000000526001 | Replaced by | |
reference set. With this reference set is possible to automatically identify that the inactive concept
|t|| 696005 | Chronobiologic disorder ||
should be replaced with the concept
|t||387605007 | Abnormal chronobiologic state ||
. This type of reference set is particularly useful for ensuring consistent use of SNOMED CT over time. The reference set mechanism here provides an easy and standardized way of managing changes to coding or documentation practice over time.