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Unified Medical Language System® (UMLS®)

2023AB UMLS® Release Notes and Bugs

What's New

The 2023AB release of the Unified Medical Language System® (UMLS) Knowledge Sources is available for download as of November 6, 2023.

The available downloads are:

UMLS Metathesaurus Precomputed Subsets

In past years, we have required the use of MetamorphoSys to install and customize the UMLS Metathesaurus. Now we are providing two ready-to-use precomputed subsets of the UMLS Metathesaurus that require no installation or customization.

UMLS Metathesaurus History Files

These files are available from the UMLS Download page: https://www.nlm.nih.gov/research/umls/licensedcontent/umlsknowledgesources.html

Please let us know if you find these files useful with comments to the NLM Help Desk (https://support.nlm.nih.gov/support/create-case/) using the subject line: “UMLS History Files”.

Metathesaurus

The 2023AB Metathesaurus contains approximately 3.36 million concepts and 15.9 million unique concept names from 185 source vocabularies.

32 English sources and 38 translation sources were updated.  These include MeSH®, MedDRA, RxNorm, and SNOMED CT® (English and Spanish).  For 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.

MetamorphoSys

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 to authenticate with an identity provider with the UTS when downloading the files.

UMLS Learning Resources
2023AB 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 REST API include the updated release.

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UMLS REST API authentication has changed. You can now authenticate by simply appending an apiKey parameter to your request, for example:

https://uts-ws.nlm.nih.gov/rest/content/current/CUI/C0155502/atoms?apiKey={{YOUR_API_KEY}}. 

Authentication via ticket-granting tickets (TGTs) and service tickets is deprecated, but we will continue to accept API authentication via this method until the end of 2023.

UMLS API Search Endpoint:

Validating API Keys: We are now offering an API endpoint for validating API keys. This is useful for application developers who need to ensure that their users are UMLS licensees. Make a request that includes both your API key (validatorApiKey) and the API key of the user of your application (apiKey).

For example: https://utslogin.nlm.nih.gov/validateUser?validatorApiKey=YOUR_API_KEY&apiKey=USER_API_KEY

Deprecated Subsets and Content Views API Endpoints are shutting down as of December 31, 2023: These endpoints were deprecated in May of 2022. Source-Asserted Subset information and Content View information can be retrieved from the UMLS Metathesaurus files.

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: https://www.nlm.nih.gov/research/umls/implementation_resources/community/index.html

Want to add your tool? Send a request to the NLM Help Desk (https://support.nlm.nih.gov/support/create-case/) 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:

We value your feedback! For more information about improvements we have made to the UMLS based on user feedback, as well as information about UMLS use in general, see our UMLS User Feedback Page: https://www.nlm.nih.gov/research/umls/implementation_resources/community/user_feedback.html



For information on the Unified Medical Language System (UMLS), consult the UMLS homepage at: https://www.nlm.nih.gov/research/umls.

The latest Release Notes list all known issues, including bugs and fixes, and are available at: https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/notes.html.

UMLS data files and MetamorphoSys are available by download from the UMLS Web site at: https://www.nlm.nih.gov/research/umls/licensedcontent/umlsknowledgesources.html. Users must have an active UMLS Terminology Services (UTS) account to download the files. All files must be downloaded into the same directory.  MetamorphoSys must be unzipped before it can be used.


Bugs

There are no known problems for the 2023AB release. 

Please send any issues or concerns to NLM Customer Service.

UMLS Problems (Bugs) for Previous Versions

Release information for the RRF Browser

Last Reviewed: November 6, 2023