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2009 MARCH–APRIL No. 367
April 20, 2009 [posted]

UMLS® 2009AA Release Available

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T he 2009AA release of the UMLS Knowledge Sources is available for download as of April 6, 2009. For more information about the release, see the What's New section of the Release Documentation.

RxNorm and SNOMED CT® are also available for download.

In the new UMLS Release there are:

Additional release statistics may be found at // Detailed information about the new and updated Metathesaurus sources is also available.

To access the UMLS Release files, you must have an active UMLS Metathesaurus® license and a valid UMLSKS account. You will be prompted for your UMLSKS Login ID and Password when downloading the files.

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 training materials and other information in the New Users' Guide.


As always, the production and mailing of the UMLS DVDs occur about four weeks after the release is made available for download. Those licensees who requested the DVD for the previous release (2008AB) will automatically receive a DVD copy of the current release. If you did not receive the previous release on DVD and want the current release on DVD, send an e-mail to and include your license code in the message.

Source Release Documentation

Two new tabs have been added to the Source Release Documentation Web pages under "Statistics and sample data": Semantic Type and Source Overlap. 2009AA Source pages will be published following the release at //

SNOMED CT Source Restriction Level (SRL) Change

The Source Restriction Level value in the 2009AA UMLS Metathesaurus has been changed from "4" to "9" for the following sources:

There are no changes to the terms of the license, only to the encoding of the SRL in the Metathesaurus. SRL data is encoded in Metathesaurus files: MRCONSO.RRF (MRSO in original release format) and MRSAB.RRF.

UMLS® 2009AA Release Available. NLM Tech Bull. 2009 Mar-Apr;(367):e17.

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