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Unified Medical Language System® (UMLS®)

2016AA UMLS® Release Notes and Bugs

What's New


The 2016AA Metathesaurus contains more than 3.25 million concepts and nearly 13 million unique concept names from over 190 source vocabularies.

2 new sources

  • CCS (Clinical Classifications Software)
  • NANDA-I (NANDA-I Taxonomy II)

1 new LOINC (LNC) translation source

  • LNC-DE-AT (German, Austria)

1 source removed

  • NAN (NANDA nursing diagnoses: definitions and classification)

2 new content views

  • LOINC Top 300+ Lab Orders
  • LOINC Panels and Forms

2 content views removed

  • UMLS enhanced VA/KP Problem List Subset of SNOMED (Level 0+SNOMED)
  • UMLS enhanced VA/KP Problem List Subset of SNOMED (Level 0+SNOMED+MDR)

55 English sources and 38 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.


  • A full Metathesaurus subset now requires 25.5 GB of disk space.
  • The active release requires 24.8 GB of disk space.

SPECIALIST Lexicon and Lexical Tools

  • The SPECIALIST Lexicon has been updated (2016Release).
  • The Lexical Tools have been updated (2016 Release) and integrate data from the SPECIALIST Lexicon, 2016 Release. The Lexical Tools include the Full and Lite versions of lvg.2016.
  • The Metathesaurus index files were processed using the updated lvg files.

UMLS Learning Resources
2016AA 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 2016AA release. Please send any issues or concerns to NLM Customer Service.

UMLS Problems (Bugs) for Previous Versions

Release information for the RRF Browser