Thrombin generation was initiated by adding 4 μM phospholipid and 1 pM TF to whole (A) or defibrinated (B, C) plasmas. CAT detects higher thrombin generation in the presence of fibrinogen than in its absence because fibrin-bound thrombin is protected from inhibition by antithrombin III but can still cleave fluorogenic substrate (3, 56, 57). A, B) Symbols are: NPP (○), patient plasma (●). C) Thrombin generation was initiated by adding 4 μM phospholipid and 1 pM TF to defibrinated NPP (○), defibrinated patient plasma (●), and defibrinated NPP plus FVIII (✞, 225%, final). Data show mean and standard deviations from experiments performed in triplicate in three independent assays for whole plasmas, and in triplicate in two to five independent assays for defibrinated plasmas.