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Unified Medical Language System® (UMLS®)

2014AB UMLS® Release Notes and Bugs

What's New


The 2014AB Metathesaurus contains more than 3 million concepts and 11.9 million unique concept names from over 150 source vocabularies.

Three new sources added: 

  • Library of Congress Subject Headings, Northwestern University Subset (LCH_NW)
  • National Drug File – FDA SPL (NDFRT_FDASPL)
  • National Drug file – FMTSME (NDFRT_FMTSME)

Two new mappings added:

  • Library of Congress Subject Headings, Northwestern University Subset, to MeSH:  MAPSETCUI C3826807 in MRMAP and MRSMAP
  • SNOMED CT to ICD10-CM Refset:  MAPSETCUI C3853366 in MRMAP and MRSMAP

One new content view added:

  • US Extension Content View – indicates that a specific atom belongs to the US Extension to SNOMED CT and carries the NLM Module ID of “731000124108” 

23 English sources and 10 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.


  • LOINC Answer concepts (“LA” codes) now are included in the Metathesaurus.  They are connected in MRREL to their LN atoms via the “has_answer” relationship label.  The sequence in which the answer appears in the answer list is an attribute in MRSAT (ATN = “SEQ_NO”) of the relationship (RUI) between the 2 concepts.

National Drug File - FDA SPL (NDFRT_FDASPL)

  • NDFRT_FDASPA only asserts relationship and does not contribute any terms to the Metathesaurus.

National Drug File - FMTSME (NDFRT_FMTSME)

  • NDFRT_FMTSME only asserts relationship and does not contribute any terms to the Metathesaurus.

NCI Thesaurus

  • Each of the 22 NCI subsources now has its own RSAB in the Metathesaurus, with SRL=0.  As a result there are 22 additional RSABs in the Metathesaurus.  All NCI subsources belong to the newly created source family “NCI” and each new RSAB begins with the prefix “NCI_”.
  • Users of this content are expected to abide by the terms of the UMLS Metathesaurus License agreement as outlined in Appendix 1
  • The 22 new RSABs in the NCI source family are:
    1. NCI_BioC
    2. NCI_BRIDG
    3. NCI_CDC
    4. NCI_CDISC
    5. NCI_CRCH
    6. NCI_CTCAE
    8. NCI_DCP
    9. NCI_DICOM
    10. NCI_DTP
    11. NCI_FDA
    12. NCI_ICH
    13. NCI_JAX
    14. NCI_KEGG
    16. NCI_NCI-HL7
    17. NCI_NCPDP
    18. NCI_NICHD 
    19. NCI_PID
    20. NCI_RENI
    21. NCI_UCUM
    22. NCI_ZFin


  • A full Metathesaurus subset now requires 23.7 GB of disk space.
  • The active release requires 22.8 GB of disk space.

UMLS Learning Resources
2014AB Source Release Documentation Web pages will be published following the release.

Users who are new to the UMLS are encouraged to review the New Users' homepage. This page includes the new UMLS Quick Start Guide, online demonstrations, step-by-step guides, and a link to UMLS training materials.


There are no known problems for the 2014AB release. Please send any issues or concerns to NLM Customer Service.

UMLS Problems (Bugs) for Previous Versions

Release information for the RRF Browser