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Unified Medical Language System® (UMLS®)

SNOMED CT® to ICD-9-CM Rule Based Mapping to Support Reimbursement

Data Files

Map VersionDerived from SNOMED CT versionDerived from ICD-9-CM versionDocumentation
June 2009 July 2008 International Release 2008 Documentation

The U.S. Department of Health and Human Services (HHS) has set a goal for the nationwide implementation of an interoperable health information technology infrastructure to improve the quality and efficiency of health care. Achieving this goal will require that key clinical data elements are captured or recorded in detailed, standardized form (using standard vocabularies, codes, and formats) as close to their original sources (patients, health care providers, laboratories, diagnostic devices, etc.) as possible. If these standardized clinical data can also be used to generate HIPAA- compliant billing transactions automatically, this will provide another incentive for adoption of clinical data standards. For automated generation of bills from clinical data to become a reality, robust mappings from standard clinical terminologies to the HIPAA code sets must be created.

HHS has given the National Library of Medicine the responsibility for funding, coordinating, and/or performing official mappings between standard clinical terminologies and HIPAA code sets. Several mappings are in various stages of development and technical validation following a set of basic mapping project assumptions. The draft “SNOMED CT to ICD-9-CM Rules Based Mapping to Support Reimbursement ” is one such map. It relates the July 2008 International Release of SNOMED Clinicial Terms (SNOMED CT) to the 2008 version of the International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM). The use case for the mapping assumes that SNOMED CT is used for clinical descriptions and that ICD-9-CM will be used for administrative and reimbursement purposes. The map is thus unidirectional from descriptive SNOMED CT codes to ICD-9-CM codes.

Scope of the Map
The draft map consists of approximately 5,000 mappings representing the SNOMED CT terms most commonly used by Kaiser Permanente and the University of Nebraska. It is designed to support administrative reporting and reimbursement processes originating with data sets where SNOMED CT is the core terminology for clinical descriptive purposes. It provides a validated concept-based mapping to ICD-9-CM, recognizing that in some selected cases, further processing of ICD-9-CM codes may be required for specialized business applications.

Creation of the Map
SNOMED Terminology Solutions™ (STS), a division of the College of American Pathologists (CAP), developed the map on behalf of NLM. The American Health Information Management Association Foundation (AHIMA Foundation), on behalf of the Centers for Disease Control and Prevention (CDC) National Center for Health Statistics (NCHS), completed a collaborative review and validation of the draft map to ensure that the result accurately reflects the meaning and usage of ICD-9-CM. James Campbell, MD, at the University of Nebraska, was also instrumental in the development of this draft map.

License Requirements
The draft map is available to all licensees of the UMLS Metathesaurus. However, use of this map is governed by users' specific licenses to use the two vocabularies in the mapping. This draft map is therefore usable by people who have a SNOMED CT license (ICD-9-CM is freely available). 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. See the License Agreement for Use of the UMLS Metathesaurus for details.

Comments and Questions
Users are encouraged to download, evaluate and test the map. Please email comments and questions about this draft map to NLM Customer Service with "Comments re Reimbursement Map" in the subject line.