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Unified Medical Language System® (UMLS®)

SNOMED CT to ICD-10-CM Map

Current Data Files

SNOMED CT to ICD-10-CM Map VersionDerived from SNOMED CT versionDerived from ICD-10-CM versionDocumentationNumber of SNOMED CT Concepts
SNOMEDCT_ICD10CM_map.201312 September 2013 US Edition 2013 Release Notes (PDF) 46,767

 

Past Data Files from:

2013

SNOMED CT to ICD-10-CM Map VersionDerived from SNOMED CT versionDerived from ICD-10-CM versionDocumentationNumber of SNOMED CT Concepts
SNOMEDCT_ICD10CM_map.201306 January 2013 International Release 2013 Release Notes (PDF) 35,963

2012

SNOMED CT to ICD-10-CM Map VersionDerived from SNOMED CT versionDerived from ICD-10-CM versionDocumentationNumber of SNOMED CT Concepts
SNOMEDCT_ICD10CM_map.201206 - Final Release July 2011 International Release 2011 Release Notes (PDF) 15,613
SNOMEDCT_ICD10CM_map.201202 - Preview Publication July 2011 International Release 2011 Release Notes (PDF) 7,277

 

Supporting Materials

Introduction

SNOMED CT (Systematized Nomenclature of Medicine-Clinical Terms) is considered to be the most comprehensive, multilingual clinical healthcare terminology in the world. It is designed for use in clinical documentation in the Electronic Health Record (EHR).  The purpose of the SNOMED CT to ICD-10-CM map (herein referred to as “the Map”) is to support semi-automated generation of ICD-10-CM codes from clinical data encoded in SNOMED CT for reimbursement and statistical purposes.

Use cases supported

The Map can be used in the following scenarios:

  • Real-time use by the healthcare provider – In this scenario, the Map is embedded in the problem list application of the EHR used by the physician or other healthcare provider. At the end of a clinic encounter, the clinician updates the problem list, which is encoded in SNOMED CT. The Map-enabled problem list application outputs a list of ICD-10-CM codes based on algorithmic evaluation of map rules, which makes use of patient context (e.g. age, gender) and co-morbidities (other problems on the problem list) to identify the most appropriate candidate ICD-10-CM codes, in accordance with ICD-10-CM coding guidelines and conventions. If necessary, the clinician is prompted for additional information to decide between alternative codes, or to refine the output codes. The clinician confirms the suggested ICD-10-CM codes. (See the I-MAGIC algorithm and demo page)
  • Retrospective coding by coding professionals – In this scenario, the Map is used within an application to suggest candidate ICD-10-CM codes to coding professionals based on a stored SNOMED CT encoded problem list. The degree of automation can vary. Textual advice can be displayed in cases where automated rule processing is not available.

Mapping methodology

The mapping methodology follows closely that of the SNOMED CT to ICD-10 Crossmap Project, a collaborative project between the IHTSDO and the World Health Organization. Dual independent mapping by trained terminology specialists is employed to assure quality and reduce variability. Identical maps created independently are accepted as final, while discordant maps are reviewed by a third expert. Regular team meetings are held to discuss problematic and ambiguous cases.

Rule-based mapping

Due to the differences in granularity, emphasis and organizing principles between SNOMED CT and ICD-10-CM, it is not always possible to have a one-to-one map between a SNOMED CT concept and an ICD-10-CM code. To address this challenge, this Map follows an approach that is consistent with the approach used by the IHTSDO and WHO in the construction of the SNOMED CT to ICD-10 rule-based map.  When there is a need to choose between alternative ICD-10-CM codes, each possible target code is represented as a “map rule” (the essence of “rule-based mapping”). Related map rules are grouped into a “map group”. Map rules within a map group are evaluated in a prescribed order at run-time, based on contextual information and co-morbidities. Each map group will resolve to at most one ICD-10-CM code. In the event that a SNOMED CT concept requires more than one ICD-10-CM code to fully represent its meaning, the map will consist of multiple map groups.

Scope

All current pre-coordinated SNOMED CT concepts within three hierarchies,(Clinical findings, Events, and Situations with Explicit Context) are  potentially in scope for mapping to ICD-10-CM.  A priority list of clinically important concepts was identified based on the CORE Problem List Subset of SNOMED CT, which includes frequently seen problems, and the Convergent Medical Terminology contents donated by Kaiser Permanente. All concepts in the US Extension that are within the mapping scope are mapped. Expansion of coverage of the map to other SNOMED CT concepts will depend on user feedback and availability of resources.

Release schedule

The current 201312 release covers 46,767 SNOMED CT concepts. Compared to the 201306 release, the new SNOMED CT additions of this release come from: newly available Convergent Medical Terminology subsets, newly-added SNOMED CT concepts in the International release, the US Extension, and SNOMED CT concepts used in the Clinical Quality Measure Value Sets that are within the scope for mapping. In the future, the Map will be periodically updated to increase SNOMED CT coverage and to synchronize with new releases of the two terminologies.

File format

The Map is published primarily as four refsets in the SNOMED CT Release Format 2 (RF2) format. To support easy browsing and understanding of the Map, it is also published as a tab delimited file that can be opened as a spreadsheet. This is a “readable” version of the Map that can be understood by a non-technical individual.

License requirements

In accordance with NLM’s mapping assumptions, the Map can be used by users that are licensed to use both SNOMED CT and ICD-10-CM. 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 free in IHTSDO Member countries including the United States, in low income countries, and for approved research projects in any country, but is subject to the IHTSDO Affiliate license provisions ( incorporated in the License Agreement for Use of the UMLS® Metathesaurus® as Appendix 2). The use of ICD-10-CM is free in the US. Users in other countries may need to contact WHO for the use of ICD-10-CM.

Comments and questions

We welcome any questions, comments or suggestions that would improve the quality, accuracy and usability of the Map. Please send feedback to Dr. Kin Wah Fung, Lister Hill National Center for Biomedical Communications, National Library of Medicine through NLM Customer Service with the subject line “SNOMED CT to ICD-10-CM Map”.

Acknowledgements

We thank Dr. James Campbell (University of Nebraska) and Dr. David Berglund (National Center for Health Statistics in the Centers for Disease Control and Prevention) for their contributions to the project. We made significant use of mapping data previously produced by the IHTSDO and the UK National Health Service (NHS) Terminology Centre, which provided access to data and tools from the SNOMED CT to ICD-10 Crossmap Project, and Kaiser Permanente, which included basic mappings to ICD-10-CM in some of their CMT content.  We thank the IHTSDO, the UK NHS Terminology Centre, and Kaiser Permanente for these contributions, which significantly reduced the resources and time required to produce the SNOMED CT to ICD-10-CM Map. We also thank CAP SNOMED Terminology Solutions Professional Services of the College of American Pathologists for their review of a subset of the Map and useful feedback.