F2 and COVID-19: Although, several studies have tested prothrombin and partial thromboplastin time and were also successful.36 They found that non-survivors of COVID-19 have a D-dimer average of 2.12 μg/mL and survivors show a D-dimer average of 0.61 μg/mL.67 Another study also approved the association of poor prognosis with high levels of D-dimer in COVID-19 patients.33