Introduction: In this study, coagulation and fibrinolysis parameters and their association with disease severity were investigated in coronavirus disease (COVID-19) patients. Materials and Methods: COVID-19 patients (n = 446) admitted to our institute between 21 February 2021 and 17 March 2022, were recruited. Clinical data and staging were collected from all patients. Blood samples were collected and analyzed for several parameters of fibrinolysis and coagulation, including alpha-2-antiplasmin(α2AP) and plasminogen, thrombin activatable fibrinolysis inhibitor (TAFI), tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), D dimer, and fibrinogen levels. Results: The TAFI, fibrinogen, and tPA levels were significantly higher in participants who died compared to that of patients who recovered (p < 0.001). However, PAI-1, tPA, and TAFI were significantly higher in patients admitted to the ICU than those of the healthy controls (p < 0.001 for PAI-1 and tPA; p = 0.0331 for TAFI). Our results showed that stage C and D COVID-19 patients had significantly higher levels of PAI-1 (p = 0.003). Furthermore, stage D COVID-19 patients had significantly higher tPA and TAFI values (p = 0.003). Conclusions: Hypofibrinolysis was the most prevalent condition among patients with severe COVID-19. In this study, several coagulation markers were elevated, making them suitable prognostic markers for hypofibrinolysis.

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 ® 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.