F5 and hemorrhagic disease: Activation of FV is mediated by thrombin or the active form of factor X with cleavage at 3 arginine residues (Arg709, Arg1018, and Arg1545) and subsequent removal of the protruding B domain.[4] FV is inactivated by cleavages at Arg306, Arg506, Arg679, and Lys994.[4] Congenital factor V deficiency (FVD) is 1 of rare bleeding disorders (RBD) and is characterized by low or undetectable plasma FV levels.