A new, rapid, chemiluminescence enzyme assay for the detection of heparin-induced thrombocytopenia: a comparison between functional and immune heparin-induced thrombocytopenia assays.

Background: Heparin-induced thrombocytopenia (HIT) is a potentially fatal complication of therapy with unfractionated or low molecular weight heparins that can result in thrombocytopenia and thrombosis. Timely clinical and laboratory diagnoses are imperative to prevent further morbidity and mortality. Objectives: To evaluate a rapid high-sensitivity chemiluminescence luminescence enzyme immunoassay (HISCL HIT IgG assay) compared with automated and ELISA antigen assays and heparin-induced platelet activation (HIPA) functional assays on samples healthy donors, patients suspected of having HIT, and other patient subgroups. Methods: The HISCL HIT IgG, HemosIL AcuStar HIT-IgG, HemosIL HIT-Ab Results: Of the 67 HIPA-positive samples, 67 were positive by the HISCL HIT IgG assay. Of the 142 HIPA-negative samples, 104 were negative with the HISCL HIT IgG assay (specificity 73.2%), compared with 97 of 142 negative results with the HemosIL AcuStar HIT-IgG assay (specificity 68.3%). The other assays exhibited lower specificity. The HISCL HIT IgG Assay Kit had no false positive results in samples with potentially interfering substances. Conclusions: The HISCL HIT IgG assay had 100% sensitivity and superior specificity compared with other antigen assays. Good correlation was observed between plasma and serum samples, and the time to result was ∼25% faster than the HemosIL AcuStar HIT-IgG assay.