SNOMED CT is a multilingual clinical terminology that covers a broad scope of clinical concepts to an appropriate level of detail for international use. In addition, it provides an extension mechanism that allows SNOMED CT to be customized to address terminology needs that are not met by the International Edition. This mechanism enables new concepts, relationships, descriptions and reference sets to be added to support national or local needs.
However, not every new terminology requirement requires a SNOMED CT extension to be created. Potential extension producers should be aware of situations in which it is beneficial to create an extension, and situations where alternatives may be preferable. The following table provides a summary.
|Create an extension when ...||An extension is not required when ...|
When a SNOMED CT extension is required, the extension may serve a range of purposes. Successful extension producers must clearly understand the requirements and purpose of their extension, before deciding which types of SNOMED CT artifacts should be included. Table 3-1 below shows some typical purposes for a SNOMED CT extensions. For each purpose, the table includes some common use case examples and a list of SNOMED CT artifacts that should be included. For more information about each of these purposes, please click on the corresponding diagram.
Table 3-1: Purposes and use cases for extensions
Use Case Examples