Exploiting UMLS Semantics for Checking Semantic Consistency among UMLS concepts

OBJECTIVES To quantify semantic inconsistency in UMLS concepts from the perspective of their hierarchical relations and to show through examples how semantically-inconsistent concepts can help reveal erroneous synonymy relations. METHODS Inconsistency is defined in reference to concepts from the UMLS Metathesaurus. Consistency is evaluated by comparing the semantic groups of the two concepts in each pair of hierarchically-related concepts. A limited number of inconsistent concepts was inspected manually. RESULTS 81,512 concepts are inconsistent due to the differences in semantic groups between a concept and its parent. Four examples of wrong synonymy are presented. CONCLUSIONS A vast majority of inconsistent hierarchical relations are not indicative of any errors. We discovered an interesting semantic pattern along hierarchies, which seems associated with wrong synonymy.