A sensitive and specific functional flow cytometric assay for the diagnosis of heparin-induced thrombocytopenia.
A functional flow cytometric assay (FCA) for the immediate diagnosis of heparin-induced thrombocytopenia (HIT), with simultaneous compatibility testing for alternative anticoagulant therapies, has been developed to provide rapid and reliable results which effectively support patient management. The assay provides results within 1-2 h, uses readily available non-radioactive reagents, and employs standard equipment. Using the highly sensitive annexin V protein probe, the method detects activated platelets induced by heparin immune-complexes, with 300-fold increased binding to activated platelets. Twenty-five samples from patients clinically-suspected of having HIT (131 tests) and 10 normal control (NG) samples (36 tests) were simultaneously tested with unfractionated heparin (UH) and low-molecular-weight heparin (LMWH), and by the radioactive serotonin-release assay (SRA) (62 and 16 tests respectively). The FCA highly correlated with the SRA, showing 100% specificity and 95% sensitivity. Moreover, the FCA exhibited higher resolution between positive and negative samples (an average value of 8.6-fold the NC versus 4.0-fold the NC by SRA). The LMWH showed concordant results with UH (r = 0.95). We conclude that the functional FCA for HIT is practical, specific and sensitive, thereby permitting the rapid diagnosis of HIT and the suitability of alternative therapies.
Tomer
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Department of Medicine, Emory University, Atlanta, Georgia, USA.
D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006493:Heparin / Q000009:adverse effects*; D006495:Heparin, Low-Molecular-Weight / Q000009:adverse effects; D006801:Humans; D012680:Sensitivity and Specificity; D013921:Thrombocytopenia / Q000139:chemically induced / Q000175:diagnosis*
D006495:Heparin, Low-Molecular-Weight; D006493:Heparin