Comparison of HIT Tests in Patients with COVID-19 and Thrombocytopenia

Thrombosis and coagulopathy have been found to be the most prevalent complications in patients with COVID-19. Thromboprophylaxis to prevent thromboembolic events is recommended for hospitalized COVID-19 patients. Heparin-induced thrombocytopenia (HIT) is a known complication of heparin use. This study aimed to determine the incidence of HIT among admitted patients with confirmed COVID-19 by PCR. In this study, two different HIT assays, rapid immunoassay (STic Expert HIT, Stago) and H-PF4 specific enzyme-linked immunosorbent assay (Asserachrom (R) HPIA - IgG), were performed. Of 200 patients with confirmed COVID-19, we identified 49 patients who met the possibility of HIT (low platelet count and high D-Dimer level). Only five (10.2%) had a positive HIT rapid test. However, none of the tested samples tested positive by ELISA. Thrombosis was reported in two of five (40%) patients. Further extensive studies are required to determine the prevalence and clinical significance of a positive HIT test among patients with COVID-19.