UMLS Metathesaurus Vocabulary Documentation

The UMLS Metathesaurus Vocabulary Documentation provides basic information about the source vocabularies represented in the UMLS Metathesaurus.

Vocabularies can be filtered by name, language, when they were last updated in the UMLS, and category restriction level.

Each source abbreviation is linked to a source synopsis page which includes a source description and update frequency. From the synopsis, there is a gray menu at the top of the page which leads to source metadata, statistics, source representation, and Metathesaurus representation. Each page is explained in more detail below.

Metadata: Lists source contact information, naming, and category restriction level.

Statistics: Counts of Semantic Types, Term Types, Attributes, Relationships, and Definitions for each UMLS source vocabulary.

Source Representation: Lists specific source data elements and provides information on their representation in the UMLS Metathesaurus. Data elements include changes to formatting, source-provided files, and file details.

Metathesaurus Representation: Contains UMLS Metathesaurus data elements and traces them back to the specific source data that populates them. Data elements include changes to formatting, atoms, attributes, definitions, relationships, and mappings.

Below are pictures and links to vocabulary documentation pages for SNOMED CT and LOINC.

Appendix 1 of the UMLS Metathesaurus License Agreement also has a list of all vocabularies and category restrictions.

Questions? Please contact us through the NLM Help Desk.