As the release file formats contain a number of concept enumerations, it is necessary to define sets of concepts that represent the allowed values. As well as the enumerated values, other metadata supporting the extensibility mechanism and the concept model is required.
The concept 900000000000441003 |SNOMED CT Model Component (metadata)|is a subtype of the root concept( 138875005 |SNOMED CT Concept|), and contains the metadata, supporting the release.
The subtypes of 900000000000441003 |SNOMED CT Model Component (metadata)|are described in the following table and the top three levels of the hierarchy are shown in the figure below this.
The metadata that supports the extensibility mechanism, and is discussed in more detail in the Reference Sets Guide.