The effect of C4BP on thrombin generation in normal pooled plasma. Thrombin generation curves in normal pooled plasma without APC (▲), with 4 nM APC (△), and with 4 nM APC and 500 nM C4BP (●). Inset: percentage of ETP as a function of C4BP concentration in normal pooled plasma in the absence of APC (○) or in the presence of APC (●).