TFPI titration of thrombin generation in PRP. Control PRP (●) and FV-deficient PRP (patient PD II, ▴) were supplemented with increasing amounts of recombinant full-length TFPI and coagulation was initiated with 50pM of TF in the presence of collagen (10 μg/mL). The peak height of thrombin generation is plotted as a function of the concentration of added TFPI.