is designed to allow the to be enhanced by adding that meet national or local requirements. are managed by or who have been issued with a , which distinguishes the of the they maintain. An may contain of various types (e.g. , , , and including used for a variety of purposes).
is a detailed clinical terminology which covers a broad scope. However, some groups of users will need additional , or to support national, local or organizational needs.
This section explains the structures that enable ( ) and to add , , and to the .
The mechanism allows to be adapted to address the terminology needs of a country or organization which are not met by the . The mechanism provides a structure within which the components of each are uniquely identified and attributed to a specific issuing organization. This ensures that, when instance data containing content from different if communicated, the provenance of each referenced is clear and ambiguity is avoided. Since the and all share the same common structure, the same application software can be used to enter, store and process information from different extensions. Similarly, can be constructed that refer to content from the and a variety of .
The common structure also means that, content developed by one organization can where relevant be easily submitted for possible inclusion in a or in the .
Using the structure can also help organizations transfer responsibility for terminology to the or to another organization, subject to the of the Affiliate License.