UMLS Mapping Documentation. NLM Tech Bull. 2012 Jan-Feb;(384):b9.
The Metathesaurus chapter of the UMLS Reference Manual includes a new section on Mappings that explains how the Metathesaurus represents mappings between its source vocabularies. Mappings provide links from entities in one terminology to entities in another terminology (ex. SNOMED CT to ICD-9-CM). Metathesaurus users will find mapping data in the MRCONSO.RRF, MRSTY.RRF, MRSAT.RRF, MRMAP.RRF, MRSMAP.RRF, and MRREL.RRF files.