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Unified Medical Language System® (UMLS®)

2017AA UMLS® Release Notes and Bugs

What's New


The 2017AA Metathesaurus contains approximately 3.47 million concepts and 13.5 million unique concept names from 201 source vocabularies.

Two new NCI sub-sources:

  1. NCI_GAIA (Global Alignment of Immunization Safety Assessment in pregnancy
  2. NCI_PI-RADS (Prostate Imaging Reporting and Data System)

58 English sources and 41 translation sources were updated.  These include MeSH®, MedDRA, RxNorm, and SNOMED CT® (English and Spanish).  A complete list is available in the Updated Sources section of the Release Documentation.  For more detailed information on changes in this version of the Metathesaurus, see the Updated Sources (Expanded) section.  Additional release statistics may be found in the Statistics section.


  • CVX and DrugBank now are included as part of RxNorm.

SPECIALIST Lexicon and Lexical Tools

  • The release includes the updated SPECIALIST Lexicon (2017 Release).
  • The release includes the updated Lexical Tools (2017 Release) which integrate data from the SPECIALIST Lexicon, 2017 Release. The Lexical Tools include the Full and Lite versions of lvg.2017.
  • The Metathesaurus index files were processed using the updated lvg files.
  • The updated SPECIALIST Lexicon and Lexical Tools feature synonym enhancements that include changes to their file structure. See the SPECIALIST Lexicon and Lexical Tools Web sites for details about these file changes and other updates.


  • The full release requires 26.6 GB of disk space.
  • The active release requires 25.9 GB of disk space.

MetamorphoSys can generate custom load scripts for MySQL, Oracle, or Microsoft Access when creating a Metathesaurus subset or installing the Semantic Network. Instructions are available on the UMLS Load Scripts homepage.

UMLS Learning Resources
2017AA Source Release Documentation Web pages will be published following the release.

Additional information regarding the UMLS is available on the UMLS homepage. New users are encouraged to take the UMLS Basics Tutorial and to explore the UMLS Quick Start Guide, and other training materials.


There are no known problems for the 2017AA release. Please send any issues or concerns to NLM Customer Service.

UMLS Problems (Bugs) for Previous Versions

Release information for the RRF Browser