COVID-19 Related Laboratory Coagulation Findings
The high rate of thromboembolism in COVID-19 patients goes along with derangements in coagulation laboratory parameters. Hemostasis testing has an important role in diagnosed COVID-19 patients. Elevated D-dimer levels were found to be a crucial laboratory marker in the risk assessment of thrombosis in COVID-19 patients. The diagnostic approach also includes prothrombin time, platelet count, and fibrinogen. Other markers (activated partial thromboplastin time (aPTT), fibrinolysis parameters, coagulation factors, natural anticoagulants, antiphospholipid antibodies, and parameters obtained by thromboelastography or thrombin generation assays) have been described as being deranged, and may help understand the pathophysiology of thrombosis in COVID-19. For monitoring the heparin anticoagulant therapy, the anti-Xa assay is suggested, because the severe acute phase reaction (high fibrinogen and high factor VIII) shortens the aPTT. Recently, the post-COVID-19 vaccination immune thrombotic thrombocytopenia has been described. Although this is a rare phenomenon, awareness is important with a proper diagnostic approach.