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National Library of Medicine Technical BulletinNational Library of Medicine Technical Bulletin

Table of Contents: 2019 NOVEMBER–DECEMBER No. 431

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UMLS 2019AB Release Available

Wilder V. UMLS 2019AB Release Available. NLM Tech Bull. 2019 Nov-Dec;(431):e1.

2019 November 05 [posted]

The 2019AB release of the Unified Medical Language System (UMLS) Knowledge Sources is available for download as of November 4, 2019.

The available downloads are:

  • Full Release (UMLS Metathesaurus, Semantic Network, Specialist Lexicon and Lexical Tools, database load scripts, and MetamorphoSys for customizing your UMLS subset and browsing the data)
  • UMLS Metathesaurus Files (complete Metathesaurus data without any customization)
  • MRCONSO.RRF file (most widely used Metathesaurus file)

The 2019AB Metathesaurus contains approximately 4.26 million concepts and 15.2 million unique concept names from 211 source vocabularies.

One new MedDRA translation:

  • MDRRUS (Russian Edition of the Medical Dictionary for Regulatory Activities Terminology (MedDRA))

One new NCI sub-source:

  • NCI_CBDD (Chemical Biology and Drug Development Vocabulary)

NDF-RT update:

  • The Metathesaurus no longer includes NDF-RT, NDFRT-FDASPL, and NDFRT-FMTSME. Note that MED-RT is the successor.

67 English sources and 31 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.


  • The full release requires 31.5 GB of disk space.

Reported bugs may be viewed on the Release Notes and Bugs Web page.

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
2019AB Source Release Documentation Web pages are available.

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.

UMLS Terminology Services (UTS)
The UTS Metathesaurus Browser and the UTS SOAP API and REST API include the updated release.

In addition, the UTS SNOMED CT Browser now features the September 2019 US Edition of SNOMED CT.

UMLS User Contributions
UMLS users have extended the functionality of the UMLS in a variety of ways by developing APIs, automation scripts, and natural language processing tools. You can find a list of these on the UMLS Community web page:

Want to add your tool? Send a request to the NLM Help Desk ( with the subject line: "UMLS Community."

Be sure to include a link to your source code so that other UMLS users can adapt your tool. We are especially interested in:

  • Database load scripts
  • Transformation scripts that convert UMLS data into other formats (for example, RDF or JSON)
  • Scripts that automate any aspect of UMLS installation
  • Applications that leverage UMLS in the processing of text

By Victoria Wilder
MEDLARS Management Section

NLM Technical Bulletin National Library of Medicine National Institutes of Health