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Table of Contents: 2020 NOVEMBER–DECEMBER No. 437

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UMLS 2020AB Release Available

Wilder V. UMLS 2020AB Release Available. NLM Tech Bull. 2020 Nov-Dec;(437):e1.

2020 November 02 [posted]

The 2020AB release of the Unified Medical Language System® (UMLS) Knowledge Sources is available for download as of November 2, 2020.

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 UMLS SOAP API is deprecated as of the 2020AA release. The SOAP API will be discontinued on December 31, 2020. SOAP API users are encouraged to switch to the REST API.

Some changes are coming to UMLS Terminology Services (UTS):

  • Our sign in process will change starting November 9, 2020. You will no longer sign in to UTS with a username and password. Instead, you will be asked to sign in using an identity provider of your choice.
  • UMLS API users who authenticate with a username and password should switch to using an API key effective immediately. Username and password will no longer work starting January 1, 2021.
  • We anticipate the release of the Beta version of our new UMLS Metathesaurus Browser on November 9, 2020.

See our Fall 2020 Changes to UTS announcement for more information.


The 2020AB Metathesaurus contains approximately 4.41 million concepts and 15.9 million unique concept names from 215 source vocabularies.

One new MedDRA translation:

  • MDRBPO (Brazilian Portuguese Edition of the Medical Dictionary for Regulatory Activities Terminology (MedDRA))

Five new NCI sub-sources:

  • NCI_ACC-AHA (American College of Cardiology/American Heart Association Clinical Data Terminology)
  • NCI_BRIDG_5_3 (Biomedical Research Integrated Domain Group Model, 5.3)
  • NCI_CELLOSAURUS (Cellosaurus)
  • NCI_GDC (NCI Genomic Data Commons)
  • NCI_ICDC (NCI Integrated Canine Data Commons)

Four LNC translation sources removed: 

  • LNC-DE-CH (LOINC Linguistic Variant- German, Switzerland)
  • LNC-ES-CH (LOINC Linguistic Variant- Spanish, Switzerland)
  • LNC-FR-CH (LOINC Linguistic Variant- French, Switzerland)
  • LNC-IT-CH (LOINC Linguistic Variant- Italian, Switzerland)

NCI_CPTAC update

  • The Metathesaurus no longer includes NCI_CPTAC (Clinical Proteomic Tumor Analysis Consortium).

65 English sources and 29 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 34.1 GB of disk space.

Reported bugs may be viewed on the Release Notes and Bugs 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 to authenticate with UTS when downloading the files.

UMLS Learning Resources
2020AB 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 2020 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 Support Center 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