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Table of Contents: 2018 NOVEMBER–DECEMBER No. 425

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UMLS 2018AB Release Available

Wilder V. UMLS 2018AB Release Available. NLM Tech Bull. 2018 Nov-Dec;(425):e1.

2018 November 06 [posted]

The 2018AB release of the Unified Medical Language System (UMLS) Knowledge Sources is available for download as of November 5, 2018.

The 2018AB Metathesaurus contains approximately 3.82 million concepts and 14 million unique concept names from 207 source vocabularies.

Three new NCI sub-sources:

  • NCI_CDISC-GLOSS (CDISC Glossary Terminology)
  • NCI_CTCAE_3 (Common Terminology Criteria for Adverse Events 3.0)
  • NCI_CTCAE_5 (Common Terminology Criteria for Adverse Events 5.0)

One new RxNorm subsource:

  • USP (USP Compendial Nomenclature)

One source abbreviation (SAB) change:

  • NCI_CTRP-SDC is now NCI_CTRP. The source name is the same (Clinical Trials Reporting Program).

National Drug File - Reference Terminology (NDF-RT) update:

  • This is the final release that will include NDFRT, NDFRT_FDASPL, and NDFRT_FMTSME. NDF-RT will not appear in 2019AA or subsequent releases.
  • Note that Medication Reference Terminology (MED-RT) is the successor to NDF-RT.

The update affected 66 English sources and 31 translation sources. 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 29.1 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
The 2018AB 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 2018 US Edition of SNOMED CT. 

By Victoria Wilder
MEDLARS Management Section

NLM Technical Bulletin National Library of Medicine National Institutes of Health