Comparative study of LOINC and SNOMED CT in panel mapping: enhancing interoperability in laboratory testing.

Background: We aimed to evaluate and compare the applicability of Logical Observation Identifiers Names and Codes (LOINC) and SNOMED CT in mapping frequently requested panel tests.

Method: Frequently requested panel tests were identified from the test records of two major referral laboratories. Subsequently, LOINC and SNOMED CT mappings were cross-validated, and the results were classified based on pre-defined criteria. A consensus was reached among the teams. A comparative structural analysis was performed by aligning the mapped SNOMED CT concepts with LOINC codes and visualizing the selected items with conditionality to evaluate the differences in representation.

Results: We conducted 23 panel tests. Exact mapping was achieved for 87.0% of the panel tests using LOINC: two failures were recorded due to the lack of a suitable code, and one panel test was classified as narrowly mapped. In contrast, SNOMED CT achieved the exact mapping for 78.2% of the panel tests, with 12 mappings requiring post-coordination to represent the test concepts. SNOMED CT mapping failures stemmed from missing primitive concepts and limited pre-coordinated codes. LOINC offered detailed component specifications and predefined panel codes. In contrast, SNOMED CT relied on post-coordination to address gaps in the pre-defined codes, allowing the addition of new combinations where necessary.

Conclusion: LOINC demonstrated advantages in mapping frequently performed panel tests with higher exact mapping rates and structured panel codes. However, leveraging SNOMED CT's flexibility through initiatives such as the LOINC Ontology project could enhance interoperability and standardization in laboratory data exchange.