Logical Observation Identifiers Names and Codes for In Vitro Diagnostic Tests  

Article No. 44802


As FDA seeks to encourage consistency in the coding of IVD tests, this guidance addresses questions regarding the distribution of LOINC codes by IVD test manufacturers to users, primarily clinical laboratories and software vendors.


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Information from IVD tests form a significant proportion of all EHRs. Laboratories commonly associate a LOINC® (Logical Observation Identifiers Names and Codes; owned, developed, and curated by the Regenstrief Institute)1 code with each test being performed by a laboratory.

For each IVD test, LOINC provides a unique numeric code associated with test attributes that identify the type of IVD test such as the component, property, time, system, scale and method.2 At present, LOINC is the IVD coding system that is most widely used by clinical laboratories and EHRs, and is the IVD coding standard recommended by the Office of the National Coordinator for Health Information Technology (ONC) in the U.S. Department of Health and Human Services (HHS) as an essential part of meaningful use. LOINC is a partially FDA-recognized consensus standard, where the recognition is limited to IVD tests.