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Unified Medical Language System® (UMLS®)

2017AB UMLS® Release Notes and Bugs

What's New


The 2017AB Metathesaurus contains approximately 3.64 million concepts and 13.9 million unique concept names from 201 source vocabularies.

One new NCI sub-source:

  1. NCI_NCI-HGNC (NCI HUGO Gene Nomenclature)

One removed source:

  1. Medi-Span data (SAB=MDDB) has been removed from RxNorm at Wolters Kluwer’s request. As of October 2017, Medi-Span data will not be included in the RxNorm or UMLS releases.

59 English sources and 30 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.

Data Changes

  • MRHIER file change: The maximum length for the HCD field is now 100 characters.


  • The full release requires 27.4 GB of disk space.
  • NLM ceased production of the separate Active Release download for each UMLS Release. The full release includes the option to select the Active Subset during installation, as one of the options in the Default Subset Configuration window. The Active Subset option is equivalent to the Active Release.

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.

Release Information
To access the UMLS Release files, you must have an active UMLS Metathesaurus® License and a valid UTS account.  You will be prompted for your UTS username and password when downloading the files. 

UMLS Learning Resources
2017AB 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.


Title: MRCONSO.RRF error
Problem: MRCONSO.RRF contains an incorrect row listing SAB=SRC and TTY=PT.  PT is not a valid term type for SAB=SRC.
The incorrect row is: C4318590|ENG|P|L14292498|PF|S17373750|Y|A28572588||||SRC|PT|NOCODE|PICRASMA EXCELSA (ingredient)|0|N||
Solution: This error will be corrected in the 2018AA Release.
Date Posted: November 6, 2017

UMLS Problems (Bugs) for Previous Versions

Release information for the RRF Browser