Relationship groups in SNOMED CT.

Relationship groups are a construct which is particular for the representation of concepts in SNOMED CT. In this paper, the July 2008 version of SNOMED CT is analyzed to determine the usage of relationship groups. Relationship groups are used with 36 out of 65 relations, playing a role in 28% of all concepts. Relationship groups are used in the concept types: "procedure" (including "regime/therapy"), "finding" (including "disorder"), "situation with explicit context" and "specimen". Examples are used to extract the purposes for using role groups, after which alternative approaches are discussed. The results indicate that relationship groups can be replaced by a small number of types of relationships such as "has sign" or "has subprocess".