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Unified Medical Language System® (UMLS®)

Nursing Problem List Subset of SNOMED CT

Current Data Files

Nursing Problem List Subset FileDerived from US Edition of SNOMED CT versionDerived from UMLS Metathesaurus versionNumber of Concepts

March 2014




Past Data Files

Nursing Problem List Subset FileDerived from SNOMED CT International Release versionDerived from UMLS Metathesaurus versionNumber of Concepts

January 2012 



July 2010 

2010AB 368


The main purpose of the Nursing Problem List Subset of SNOMED CT is to facilitate the use of SNOMED CT as the primary coding terminology for problem lists or other summary level clinical documentation.

The use of a common list of SNOMED CT concepts will maximize data interoperability among institutions. However, local problem list vocabularies often need to be expanded to satisfy specific user needs. Users should check to see if SNOMED CT contains terminology for concepts they need to fulfill their local requirements and use case. The UMLS Terminology Services (UTS) includes a SNOMED CT browser that may be used for this purpose. The SNOMED CT Browser is available through the SNOMED CT menu of the UTS.

If needed concepts are not found in the terminology, users are encouraged to submit them for inclusion in the US Extension of SNOMED CT. To submit a new nursing problem concept, go to U.S. SNOMED CT Content Request System (USCRS). Additional assistance on submitting requests can be found on the UMLS Video Learning Resources page, under SNOMED CT: USCRS. In this way, the link to the Nursing Problem List concepts is maintained and divergence of problem list vocabularies can be minimized. Institutions that are using their own problem list vocabularies are encouraged to map them to SNOMED CT with a focus on the Nursing Problem List concepts to facilitate data interoperability.

Choice of SNOMED CT concepts
To find the most appropriate SNOMED CT concepts for each problem list term, the following guidelines are used:

  • Only FSN (Fully Specified Name) SNOMED CT atoms are included (TTY = “FN”). Each SNOMED CT concept has a UMLS CUI that has at least one term (atom) from at least one nursing vocabulary. 
  • Only active SNOMED CT concepts are included.
  • Most concepts are chosen from the SNOMED CT clinical finding hierarchy

Additional resources from the UMLS
For each SNOMED CT concept in the subset, the corresponding UMLS CUI (concept unique identifier) is listed. Through this, users can have access to resources available in the UMLS e.g., additional synonyms (beyond those present in SNOMED CT itself), text definitions for many terms, and corresponding codes in other terminologies.

File description
The fields in the current version of the Nursing Problems Subset are different from previous versions so implementation of the subset can correspond with the CORE Problem List Subset of SNOMED CT.
The SNOMED CT Nursing Problem List subset data file has the following fields: (Primary Key: Snomed_CID + UMLS_CUI)

  • SNOMED_CID – conceptId of the SNOMED CT concept
  • SNOMED_FSN – SNOMED CT fully specified name
  • SNOMED_CONCEPT_STATUS – active status of the SNOMED CT concept (CURRENT = active concept)
  • UMLS_CUI – the corresponding UMLS concept unique identifier
  • OCCURRENCE – number of nursing vocabularies having this concept, not populated for concepts retired from Subset
  • USAGE – retained for compatibility with the CORE Problem list, not populated in the nursing subset.
  • FIRST_IN_SUBSET – the version of Subset first containing this concept
  • IS_RETIRED_FROM_SUBSET –  Concepts previously included in the Subset that have since been deemed inactive in SNOMED CT or retired from UMLS are marked as “TRUE”
  • LAST_IN_SUBSET – the version of Subset last containing this concept, only populated for concepts retired from Subset
  • REPLACED_BY_SNOMED_CID – Indicates the SNOMED CT concept that replaces a retired SNOMED CT concept.  In cases where an entry in the problem list is inactive due to a retired UMLS CUI, the REPLACED_BY_CID is the same SNOMED CT concept is the same as the SNOMED_CID in the active entry.

A sample database load script can be found here.

The file identifies what we hope is a useful subset of SNOMED CT, but does not include all the information likely to be required to make effective use of SNOMED CT in an application, such as synonyms that may include more clinician-friendly terms than the SNOMED CT fully-specified name. The identifiers in the file can be used to extract more complete information for these concepts from either the UMLS release files or the SNOMED CT native format files.

Update and maintenance
A new version of the subset is generally published periodically. Newly inactive SNOMED CT concepts will be flagged and additional concepts may be added if appropriate.

SNOMED CT license requirement
SNOMED CT is owned by the International Health Terminology Standards Development Organisation (IHTSDO), of which NLM is the US Member. Use of SNOMED CT is subject to the IHTSDO Affiliate license provisions (incorporated in the License Agreement for Use of the UMLS® Metathesaurus® as Appendix 2) and is free in IHTSDO Member countries including the United States, in low income countries and for approved research projects in any country.

Feedback and suggestions
We welcome any questions, comments or suggestions that would improve the quality, accuracy and usability of the subset. Please send feedback to Dr Judy Warren ( and Dr. Susan Matey (

The IHTSDO Nursing Work Group Problem List Project Team thanks the IHTSDO, the IHTSDO Nursing Work Group, and the NLM for their participation in and support of this project.