LOINC and SNOMED CT Codes to be Linked

Regenstrief Institute in Indianapolis, which owns the LOINC terminology of codes for identifying laboratory and clinical observations, and the International Health Terminology Standards Development Organisation in Copenhagen, which owns the SNOMED Clinical Terms set of codes, will link the terminologies.

Aligning how the terminologies represent the attributes of lab tests and some clinical measurements will give users a common framework to use both code sets, according to the organizations.

Daniel J. Vreeman, research scientist at Regenstrief and assistant research professor at Indiana University School of Medicine, explains the partnership and its goals:

“LOINC is a terminology with more than 72,000+ codes for clinical tests, measurements, and other kinds of observations. SNOMED CT is a large clinical terminology with codes covering many other domains: diagnoses, body parts, bacteria names, chemical substances, etc. SNOMED does have some codes for tests and measurements, but not nearly as many as LOINC. This agreement starts work by both organizations to map the LOINC representation of a particular test to the same meaning in SNOMED.

“For example, LOINC has a code for a blood hemoglobin level measurement. Under this agreement, we'd link the LOINC code for this test to the SNOMED codes for hemoglobin (the substance) and blood specimen. We're doing this in such a way that SNOMED doesn't have to re-create a concept code for every test that already exists in LOINC. We're just making the relationships between these different elements explicit--and computable. Another thing we'll be doing relates to test values for categorical measurements. For these non-numeric tests, we'll be linking the LOINC test code to a set of possible test values represented by SNOMED codes. For example, the LOINC code for the test that determines your blood type (ABO Group) would be linked to SNOMED codes for Type A, Type O, etc. These linkages will make it easier to use standard codes for reporting non-numeric test values.

“We don't currently have a timeline for when this work will be completed. We're starting with high priority areas first (lab tests, clinical measurements like vital signs) and will see how things progress. But, it's also important to realize that this will be an ongoing effort as both terminologies continue to grow. Twenty years since LOINC was first born, we thought the pace would have slowed by now, but we're still adding thousands of new codes each year because the field keeps advancing. So, we view this as a journey, not a destination.”