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Unified Medical Language System® (UMLS®)

2013AB UMLS® Release Notes and Bugs

What's New


The 2013AB Metathesaurus contains more than 2.9 million concepts and 11.4 million unique concept names from over 160 source vocabularies.

Four new sources were added:

  • Anatomical Therapeutic Chemical Classification System (ATC)
  • Current Dental Terminology (CDT)
  • Vaccines Administered (CVX)

One new content mapping was added:

  • SNOMED CT to ICD-10

As of 2013AA, the release is available in two versions: Full and Active. The Full Release includes all source vocabularies. The Active Release includes only vocabularies that are actively updated in the Metathesaurus. The Active Release is a smaller download, decreases MetamorphoSyS processing time, and provides easier access to current Metathesaurus content.

37 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.

Data Changes

  • MRCONSO file change: The maximum length for the CODE, SAUI, SCUI, and SDUI fields is now 100 characters.
  • The co-occurrences files, MRCOC.RRF and MRCOC (ORF format), are not included in the release as of 2013AB. Co-occurrence information is available on the MEDLINE/PubMED Baseline Repository (MBR) Web site.
  • The Metathesaurus no longer includes these vocabulary sources, listed by SAB:
    • MTHHL7V25 (HL7 Vocabulary Version 2.5, 7-bit equivalents)
    • MTHICPC2ICD107B (International Classification of Primary Care 2nd Edition, 7-bit Equivalents)
    • SNOMEDCT (International Release of SNOMED CT); content is available in SNOMEDCT_US
    • SNOMEDCT_USX (US Extension of SNOMED CT); content is available in SNOMEDCT_US
  • NLM no longer creates plain ASCII versions of atoms where the original string value included non-ASCII characters. As of this release the Metathesaurus does not include these ASCII terms Metathesaurus indexes reflect these changes and include modifications to maintain existing search and retrieval capabilities.
    • Use the Unicode Filter in MetamorphoSys to convert to ASCII or remove non-ASCII terms from your subset.

Logical Observation Identifier Names and Codes (LOINC)

  • LNC_AD8 (Eight-item Informant Interview to Differentiate Aging and Dementia) and LNC_MDS30 (Minimum Data Set, 3.0):
    • As of 2013AB, this content is included under SAB=LNC due to processing changes.
  • The representation of LOINC (SAB=LNC) in the Metathesaurus does not include the following content:
    • Blessed Orientation-Memory-Concentration Test
    • Borderline Symptom List - 23 Item
    • Borderline Symptom List - Supplement
    • Edinburgh Postnatal Depression Scale
    • Patient Reported Outcomes Measurement (PROMIS)
    • Test of Infant Motor Performance (TIMP)


  • A full Metathesaurus subset now requires 23 GB of disk space.
  • The active release requires 22 GB of disk space.
  • MetamorphoSys requires Java Runtime Environment (JRE) Version 1.7.

UMLS Learning Resources
2013AB 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.


1) Title: Missing source data in release files

Problem: The Full Release files did not contain data for the full list of UMLS sources. Users selected sources with missing data during installation and created subsets with no data for these sources.

Solution: NLM repackaged the files with the missing data. Users must download the new files dated February 10. Download all of the files and create a new subset.

Date Posted: February 12, 2014

2) Title: Duplicate rows in MRSAT.RRF cause errors when loading data into a MySQL database

Problem: Duplicate rows in MRSAT.RRF cause problems when loading a Metathesaurus subset into a MySQL database. Users may see an error at this command: ALTER TABLE MRSAT ADD CONSTRAINT X_MRSAT_PK PRIMARY KEY BTREE (ATUI);. The extra rows cause errors due to the duplicate primary key in the rows.

Solution: Run Metamorphosys again to recreate your subset and remove the CV_MEMBER attribute during installation by using the attributes filter.

NLM will correct this error in the next release.

Date Posted: January 7, 2014

UMLS Problems (Bugs) for Previous Versions

Release information for the RRF Browser