Upon FXa formation by either the extrinsic or intrinsic pathway of coagulation, FXa catalyzes the conversion of prothrombin to Thrombin with subsequent fibrin formation. Both the APTT and PT are affected by components (FX, FV, FII, FI) of the common pathway. The slide show entitled Tissue Factor Pathway (Extrinsic) with Common Pathway (PT) shows which components are part of this pathway.
