Scope of LOINC

The overall scope of LOINC is anything you can test, measure, or observe about a patient. We generally talk about two major divisions of the content in LOINC: Laboratory and Clinical.


The laboratory portion of LOINC covers anything that you can test, measure, or observe about a specimen. It contains the usual categories of chemistry, hematology, serology, microbiology (including parasitology and virology), toxicology; as well as categories for cell counts, antibiotic susceptibilities, and more.

Laboratory Classes


We think of "clinical" as pretty much everything except lab. The clinical portion of LOINC covers anything that you can test, measure, or observe about a patient without removing that specimen from them. LOINC has codes for observations like vital signs, hemodynamics, intake/output, EKG, obstetric ultrasound, cardiac echo, urologic imaging, gastroendoscopic procedures, pulmonary ventilator management, radiology studies, clinical documents, selected survey instruments (e.g. Glasgow Coma Score, PHQ-9 depression scale, CMS-required patient assessment instruments), and other clinical observations.

Clinical Classes

Discrete Measures and Observations

LOINC creates codes for laboratory tests and clinical observations that represent a discrete measurement such as:


We also create codes for a collection of measurements like the following:

Requesting New LOINC Content

Since its inception, Regenstrief has developed LOINC as an open standard. We welcome requests for new LOINC terms. It is because of submissions from the LOINC community that we've been able to grow and adapt so quickly. We are also always happy to receive specific suggestions about revisions or enhancements to existing content like synonyms and term descriptions as well.

When you'd like to request a term for something you think is missing, read more about how to make a submission request.