A combination of 2 rapid immunoassays significantly improves diagnostic sensitivity for heparin-induced thrombocytopenia

OBJECTIVES: To evaluate the diagnostic performance of chemiluminescent immunoassay (CLIA), latex immunoturbidimetric assay (LIA), and the combination of CLIA/LIA with respect to the functional heparin-induced platelet aggregation (HIPA) test. METHODS: An observational retrospective study was conducted on 100 patients. All samples were initially tested with CLIA on the ACL TOP AcuStar, and then we performed LIA and CLIA tests concurrently (on the same samples on the ACL TOP 970 CL) and the HIPA test. RESULTS: The CLIA test was performed on both the AcuStar and the ACL TOP 970 CL, and results were concordant: 68% of patients were negative, and 32% were positive. The HIPA test confirmed a diagnosis in 26 of 32 and identified 6 false-positive patients and 1 false-negative patient. The LIA test was performed on the ACL TOP 970 CL: 64% of patients were negative, and the remaining 36% were positive. The HIPA test confirmed a diagnosis in 24 patients and identified 12 false-positive and 3 false-negative patients. The combination of CLIA and LIA tests allowed us to categorize 27 true-positive, 13 false-positive, 0 false-negative, and 60 true-negative patients. CONCLUSIONS: The combination of CLIA/LIA provides high sensitivity with a progressively greater probability of detecting platelet-activating antibodies with a higher assay reactivity, reaching 100% when both automated assays yield moderate or strong results.