Correlation of ELISA Optical Density With Clinical Diagnosis of Heparin-Induced Thrombocytopenia: A Retrospective Study of 104 Patients With Positive Anti-PF4/Heparin ELISA

Background: Enzyme-linked immunosorbent assay (ELISA) for antiplatelet factor 4 (anti-PF4)/heparin antibodies is expressed in terms of optical density (OD). Previous studies have shown correlation between OD and heparin-induced thrombocytopenia (HIT) diagnosis. However, these were mainly laboratory based.Objective: Retrospective correlation of clinical HIT to ELISA OD.Patients/Methods: We conducted a retrospective study involving 104 patients with a positive ELISA for anti-PF4/heparin antibodies between 2008 and May 2012. For each patient, a clinical diagnosis was adjudicated based on different features including “4T scores,” laboratory results, and a 3-month clinical follow-up.Results: In this study, 28.8% of the patients were HIT positive, and 71.2% HIT negative. Patients with positive diagnosis had significantly higher mean OD (2.15 ± 0.76 vs 0.83 ± 0.62). Patients with OD 2.0 units.Conclusion: This study is a clinical co...