Coverage of patient safety terms in the UMLS metathesaurus.

The integration and large-scale analyses of medical error databases would be greatly facilitated by the use of a standard terminology. We investigated the availability in the UMLS metathesaurus of concepts that are required for coding patient safety data. Terms from three proprietary patient safety terminologies were mapped to the concepts in UMLS by an automated mapping program developed by us. From these candidate mappings, the concept that matched its corresponding term was selected manually. The reliability of the mapping procedure was verified by manually searching for terms in the UMLS Knowledge Source Server. Matching concepts in UMLS were identified for less than 27% of the terms in the study dataset. The matching rates of terms that describe the type of error and the causes of errors were even lower. The lack of such terms in the existing standard terminologies underscores the need for development of a standard patient safety terminology.