Platelet-Activating Antibodies Are Detectable at the Earliest Onset of Heparin-Induced Thrombocytopenia, With Implications for the Operating Characteristics of the Serotonin-Release Assay

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a prothrombotic drug reaction caused by platelet-activating antibodies that recognize platelet factor 4 (PF4)/heparin complexes. It is unknown whether platelet-activating antibodies are detectable at the onset of the HIT-related platelet count fall. METHODS: Available blood samples from 18 patients obtained at onset of HIT were tested using the serotonin-release assay (SRA), a test for …