Maintaining reference sets starts as soon as the reference set is specified. The maintenance process involves ensuring that the content of the reference set refers to active concepts in the release upon which the reference set depends. It also involves adding new content to the reference set, for example when additions to the dependee Release fall within the scope of the reference set specification. The alignment of a reference set with the International Release will be undertaken during the international release process, at which time a change report will be created for circulation, providing details of the changes made, in a format that can be circulated virtually to subject matter experts.
If a reference set is added data entry protocols should be updated to link to this reference set where this is found appropriate. For example, if a reference set has been developed to function as a value set for cardiovascular diseases, data entry protocols should link to the reference set in the data entry protocols used to capture cardiovascular diseases. The nature of the binding depends on the underlying information model of the protocol. Additionally, it is important to update the storage models appropriately. See, Starter Guide Chapter 3. Using SNOMED CT in Clinical Information to learn about this topic. It may also be necessary to develop queries to generate reports or views based on the new reference set data. Alternatively, an added reference set may include rules to enable decision support, which must be integrated. It may also be necessary to create or update links between reference set members and communication protocols.
The types of changes that can occur in a reference set include:
Additional information: TSG Guide Section 13.2 How to add, change or remove members of an existing reference set
The effect of changes to reference set members depends on the type of reference set and the way the reference set is used. Generally, it is important to assess the extent to which the reference set changes affect the situation in which the reference set is used, such as:
One way of determining the changes to a reference set is by creating and comparing the following two views of the reference set:
These two views make it possible to automatically identify whether a reference set member has been created, changed, reactivated or inactivated. The table below illustrates how to interpret the 'active' attribute, when comparing the delta view of the new release of the reference set with the snapshot view of the previous release of the reference set.
|Value of active column in the new release of the reference set (DELTA view)|
|Value of active column in previous release of the reference set (SNAPSHOT view)||0||Inactive member changed (not significant)||Member REACTIVATED||NO CHANGE|
|1||Member INACTIVATED||CHANGED member||NO CHANGE|
|NOT PRESENT||n/a||NEW member||n/a|