LOINC® (Logical Observations Identifiers, Names, Codes), is a clinical terminology important for laboratory test orders and results, produced by the Regenstrief Institute.

LOINC is one of a suite of designated standards for use in U.S. Federal Government systems for the electronic exchange of clinical health information. LOINC is likely to become a HIPAA standard for some segments of the Claims Attachment transaction. In 1999, it was identified by the HL7 Standards Development Organization as a preferred code set for laboratory test names in transactions between health care facilities, laboratories, laboratory testing devices, and public health authorities.

NLM supports the ongoing development of LOINC through a contract arrangement.

Additional information about LOINC and its representation in the UMLS Metathesaurus is available: