LabAlignAgent LabAlignAgent: A LOINC-Enriched Ontology-Guided Agent forCross-Hospital Semantic Alignment of EMR Laboratory Tests
Abstract
Patients often receive care from multiple hospitals, where laboratory tests are commonly represented usinginstitution-specific names, units, and reporting conventions. This heterogeneity limits semantic interoperabilityacross Electronic Medical Record systems. This study proposes LabAlignAgent, a LOINC-enrichedontology-guided agent for cross-hospital semantic alignment of EMR laboratory tests. The approach combinesdomain ontology construction, LOINC-based ontology enrichment, exact and fuzzy matching, GPTassistedsemantic verification, and rule-based alignment to harmonize heterogeneous laboratory test catalogs.The evaluation used real-world laboratory test data from two Saudi hospitals: 136 alignable tests fromKing Fahad Specialist Hospital (KFSH) and 126 alignable tests from Saudi German Hospital (SGH). In thehospital-to-LOINC normalization task, 202 out of 262 tests, representing 77.1%, were successfully mappedand enriched with standardized LOINC concepts, including 67 additional mappings recovered throughGPT-assisted reasoning beyond lexical matching alone. In the cross-hospital alignment task, 17,136 possibleKFSH–SGH pairs were reduced to 4,509 semantically plausible candidate pairs using ontology-derivedconstraints on unit and sample type. The full LabAlignAgent workflow produced 224 high-confidence crosshospitalsemantic matches, compared with 67 matches obtained by the baseline prompt-based alignmentwithout ontology enrichment. The accepted mappings were validated by a clinical pathologist, who assessedclinical equivalence using analyte, specimen, unit, method, and reference-interpretation criteria.The results show that LOINC-enriched ontology guidance and contextual semantic reasoning substantiallyimprove laboratory test harmonization across hospitals and support more interoperable EMR integration.All datasets, ontologies, lab test names, and alignment results for each strategy are publicly available inour GitHub repository at https://github.com/SarahayadAOU/LabAlignAgent.