Unified Medical Language System® (UMLS®)

Project Officer: Betsy Humphreys, M.L.S.

One of NLM's major research initiatives is the Unified Medical Language System (UMLS) Project. The UMLS comprises four principal knowledge sources:

UMLS Metathesaurus® (An important application based on the Metathesaurus is the Coach Expert Search Refinement System).
The 1994 edition maps over 190,000 concepts and over 370,000 terms from 24 defined medical vocabularies into a common lexicon.
UMLS Semantic Network
This assigns semantic types to the elements of the lexicon, and defines which relationships between semantic types are meaningful.
The SPECIALIST lexicon
This contains syntactic information for many Metathesaurus terms, component words, and English words that do not appear in the Metathesaurus. It serves as a source of information for the SPECIALIST natural language processing system.
Information Sources Map (ISM)
The ISM consists of a descriptive component (a database of information sources, generally Internet-accessible) and a procedural component, a prototype for which is currently under development in collaboration with the Clearinghouse for Networked Information Discovery and Retrieval (CNIDR).
A 4 CD-ROM set of the UMLS information sources is available for investigatory purposes. Due to the presence of proprietary information such as content from Dorland's Medical Dictionary, a license agreement must be signed.
Direct enquiries to:
Betsy Humphreys
UMLS Project Officer
Bldg. 38, Room 2W06
8600 Rockville Pike
Bethesda MD 20894 USA

NLM HyperDOC / UMLS FactSheet / April 1994