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Unified Medical Language System® (UMLS®)

Contact UMLS, Value Set Authority Center, or SNOMED CT Support:

Contact RxNorm Support:

Contact RxNav Support:

UMLS Users Listserv (UMLSUSERS-L):

NLM uses this forum to distribute official announcements about UMLS products and services.

RxNorm Announcements Listserv (RXNORM-ANNOUNCES-L):

Announcement-only list about major changes to the RxNorm release files, technical issues related to accessing the files, and other important announcements.

VSAC Announcements Listserv (NLM_VSAC_UPDATES):

Announcement-only list about new releases and other communications related to the activities of the Value Set Authority Center (VSAC).

SNOMED CT Announcements Listserv (SNOMEDCT-ANNOUNCES-L):

Announcement-only list about major changes to the SNOMED CT release files, technical issues related to accessing the files, and other important announcements.

Last Reviewed: February 24, 2025