title: The semantics of procedures and diseases in SNOMED CT.
abstract: OBJECTIVE
  SNOMED CT is emerging as a reference terminology for the entire health care process. It claims to be founded on logic-based modelling principles. In this article, we analyze a special encoding scheme for diseases and procedures in SNOMED CT, the so-called relationship groups (RGs), which had been devised to avoid ambiguities in definitions.
  
  
  METHODS
  We reformulate SNOMED CT's relationship groups in the format of description logics in order to check whether RGs serve the needs they were designed for.
  
  
  RESULTS
  We show that a considerable proportion of relationship groups represent hidden mereological relations. We also report discrepancies encountered between the defined semantics of many SNOMED CT terms and their intuitive meaning, as well as inconsistencies detected between the definition of various complex composed terms and the definition of their top-level parents.
  
  
  CONCLUSIONS
  We formulate recommendations for improving SNOMED CT by replacing most occurrences of relation groups by formally more adequate "part-of" relations.
authors.affiliation: Department of Medical Informatics, Freiburg University, Germany. stschulz@uni-freiburg.de
authors.forename: S
authors.initials: S
authors.lastname: Schulz
authors.forename: S
authors.initials: S
authors.lastname: Hanser
authors.forename: U
authors.initials: U
authors.lastname: Hahn
authors.forename: J
authors.initials: J
authors.lastname: Rogers
mesh_terms: D000715:Anatomy / Q000145:classification; D004194:Disease / Q000145:classification; D006801:Humans; D019545:Intuition; D051188:Knowledge Bases; D008490:Medical Informatics; D016347:Medical Records Systems, Computerized / Q000145:classification*; D012660:Semantics; D039061:Systematized Nomenclature of Medicine; D018511:Systems Integration; D014825:Vocabulary