Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Unified Medical Language System® (UMLS®)

LOINC To CPT Mapping

Data Files

LOINC to CPT Mapping Version Documentation
Draft LNC215 to CPT2005 Mapping README

Note: A newer version of the map is not available at this time.

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 NLM 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 “LNC215 to CPT2005 Mappings” is the first such map to be released for public review and comment. It relates the 2.15 version of Logical Observation Identifiers Names and Codes (LOINC) to the 2005 version of Current Procedural Terminology, 4th ed. (CPT). The use case for the mapping assumes that LOINC codes will be used in ordering or reporting laboratory tests and observations and that CPT codes would need to be submitted for billing purposes. The map will thus be unidirectional from orderable LOINC codes to CPT billing codes.

Creation of the Map and Future Enhancements
The draft LOINC to CPT map was created by Intermountain Health Care (IHC) under contract with the Regenstrief Institute, Inc. with funding from NLM. The draft map represents the 2000+ most common mappings contributed by people currently using LOINC and CPT in their local systems. Nearly all of the mappings are from Laboratory LOINC rather than Clinical LOINC. The resulting draft map was reviewed for accuracy by both the Regenstrief Institute, which produces LOINC, and the American Medical Association (AMA), which produces CPT.

IHC is currently updating the existing draft map to the current versions of LOINC and CPT as well as adding some logical extensions. IHC will then continue expanding the map by covering (in order):

  1. Radiology tests
  2. LOINC document names (consults, progress notes, nursing notes, etc.)
  3. More comprehensive Laboratory LOINC mappings
  4. Common clinical findings (vital signs, height, weight, blood pressure, heart rate, etc.)

Suggestions for priorities for future LOINC to CPT mappings are welcome.

Over the next few months NLM will work with CMS (Centers for Medicare & Medicaid Services) staff to develop plans for official testing and validation of the mappings.

Accessing the Map
UMLS users’ ability to use a mapping is governed by their licenses to use the two vocabularies in the mapping. This draft map is therefore usable by people who have a CPT license (LOINC is freely available). The License Agreement for Use of the UMLS Metathesaurus includes CPT and is required to download or access the mapping files.

These files are in Rich Release Format (RRF) and do not require the use of the MetamorphoSys program provided with the UMLS Knowledge Sources files. A detailed description of the mapping file formats is available from the MRMAP.RRF and MRSMAP.RRF sections of the UMLS Reference Manual.

Testing and Feedback
Production of mappings is an iterative process, which must involve testing, validation, and use in real world settings. The functionality of this and subsequent mappings will improve over time as research, testing, and use determine (a) useful ways to construct and represent complex mappings (such as those that involve conditional rules) and (b) the extent they can be applied in the real world.

We strongly encourage thorough testing of this map and feedback to NLM. In particular we would like to know:

Please email your comments to NLM Customer Support with "Comments re LOINC to CPT Mapping" in the subject line.

Last Reviewed: January 27, 2017