Current Version - Under Revision
An Extension mechanism offers many advantages to developers, vendors, terminologists, national bodies and users.
Such a mechanism allows:
- Users to access the SNOMED CT International Release and one or more Extensions through a single user interface ;
- Developers to implement SNOMED CT Extensions without developing specialized software;
- Vendors to develop and sell products to take advantage of both International Release content and Extensions ;
- Organizations to develop and share terminology that meet their business needs, without procuring software;
- SNOMED International Affiliates to develop terminology that can be shared with other organizations and considered for addition to the International Release content;
- SNOMED International Affiliates to use locally-developed terminology without potential overlap with the work of other organizations.
Concept may be:
- A national or organizational definition of a concept, which is more rigorous or specific than that generally applied to the SNOMED CT Concept ;
- An experimental procedure that is not established sufficiently to merit the inclusion in the main body of SNOMED CT but which may be in a local controlled study.
- Extension Descriptions may be colloquial synonyms for a SNOMED CT Concept or descriptions for an Extension Concept.
Relationships may be required to allow analysis packages or decision-support protocols to access
additional information about a
SNOMED CT Concept or to describe
- Links between local procedures and relevant administrative actions;
- Links between local procedures and SNOMED CT Procedures.
- Extension Reference sets may group SNOMED CT Concepts in ways that are specific to data entry contexts of a particular application or communication specification.
- Distinguishable from the main body of SNOMED CT, not only in the thesaurus, but also when stored in a patient record, query or decision support protocol;
- Distinguishable from other Extensions, in the same way as they are distinguishable from the main body of SNOMED CT ;
- Able to be distributed and processed in the same way as equivalent components from the main body of SNOMED CT without requiring specific adaptations of SNOMED-enabled applications.
The requirements for Extensions can be summarized as follows:
- Support for extra terminology components including Concepts, Descriptions, Relationships and Reference Sets:
- Globally unique identification of any terminology
component that may be used outside the scope of a limited local environment:
- The mechanism allows several organizations to issue mutually exclusive Identifiers for components of their Extensions.
- To avoid the risk of misinterpretation, this mechanism is effective in various contexts
- Within the thesaurus;
- In patient records;
- In queries, decision-support protocols or knowledge bases.
- The mechanism indicates when Concepts have moved, or are expected to move, between an Extension and the International Release, or from one Extension to another.
- A shared understanding of the responsibility of an organization that creates an
Extension and provides it for the use of other organizations. These responsibilities include:
- Maintenance of the Concept, Descriptions, Relationships, and Reference Sets ;
- Inactivation of these components as appropriate (duplication, ambiguous, outdated, etc.);
- Submission to an Member 's National Release Centre for consideration as an addition to a National Edition or to the International Release content.