Effect of protein C inhibitor on tissue factor-induced coagulation. Normal plasma (closed symbols) and PCI-deficient plasma (open symbols) were incubated with buffer (○,•), 80 (□), or 160 (▵) nmol/L of protein C inhibitor. After incubation, coagulation was started by the addition of recombinant tissue factor (Innovin, diluted by a factor 3 × 10⁴) and calcium. The formation of fibrin was measured in time as the change in turbidity at 405 nm.