Draft LOINC-SNOMED CT Mappings and Expression Associations Now Available

The Regenstrief Institute and IHTSDO are very pleased to announce that a draft file containing LOINC-SNOMED CT Mappings and Expression Associations is now available.

The draft file (called a Technology Preview in SNOMED CT lingo) is now available.

You can download the file here.

The Technology Preview file was generated as part of the cooperative agreement signed between the Regenstrief Institute and the IHTSDO in July 2013. (Read more about the collaboration).

The agreement details how SNOMED CT and LOINC will be linked through:

  1. a map of LOINC terms to post-coordinated SNOMED CT expressions
  2. a map of LOINC parts to SNOMED concepts
  3. a map between LOINC terms and existing pre-coordinated SNOMED concepts
  4. LOINC Answer sets mapped to SNOMED codes; and
  5. addition of new content in either terminology.

This Technology Preview includes artifacts related to items 1, 2, and 5 above.

The Technology Preview contains two main sets. The first is the LOINC Term to SNOMED Expression Reference Set. The LOINC Term to SNOMED Expression Reference Set contains 9730 active LOINC terms associated with post-coordinated SNOMED CT expressions. The second is the LOINC Part to SNOMED Reference Set that consists of 2121 LOINC Parts (LP) mapped to one or more SNOMED concepts.

The SNOMED CT LOINC Technology Preview is provided in UTF-8 encoded tab-delimited flat files which can be imported into any database or other software application. The file structure is SNOMED CT Release Format 2 (RF2)  compliant but only contains the full release files for the refsets (no delta, snapshot, or history) as this is the first release.

Feedback is requested on the Technology Preview release to inform future development and determine fitness for purpose. Feedback on the formatting of expressions, maps and reference sets is expected; feedback on the content of the expressions or mapping themselves is also welcome.

The IHTSDO requests that you please provide feedback by 15 December, 2014 using the online form:



The Technology Preview is distributed for evaluation purposes only. It is not for use in production clinical systems or  in clinical settings. USE WITHIN CLINICAL SYSTEMS CANNOT BE SUPPORTED AT THIS TIME.