Summary of effects of elevated plasma TFPI on thrombin generation in patients with COVID-19. COVID-19 enhances thrombin generation via multiple mechanisms, including EVs, histones, NETs, and aPL.¹³ Elevated plasma TFPI prolongs the lag time to thrombin generation but does not diminish peak thrombin. aPL, antiphospholipid antibody; FXa, factor Xa; FVIIa, factor VIIa; NET, neutrophil extracellular trap.