Respective contribution of plasma and platelet FV, as well as TFPIα, to thrombin generation in 5 F5F8D PRPs. FV-depleted plasma was reconstituted with isolated platelets of 5 F5F8D patients, as well as age- and sex-matched normal controls. LT (A) and PH (B) values for thrombin generation were plotted against functions of FV (0-20 IU/dL). Statistical difference in LT (C) and PH (D) values were calculated between F5F8D patients and normal controls. (E-F) Reconstituted PRPs of patient P4 and a normal control were supplemented with 10 ng/mL TFPIα at each FV titration. LT (E) and PH (F) values were plotted against functions of FV (0-20 IU/dL) with and without the supplemental TFPIα. **P < .01.