The Semantics of Procedures and Diseases in SNOMED® CT

Abstract

OBJECTIVES: 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.