Thrombocytes ! Clotting Factors ! The clotting factors are a group of chemicals in the blood which is responsible for the formation of blood clot. Clotting factors are usually inactive but once there is an injury to the wall of the blood vessel, they get activated. The function of clotting factors is to trigger the formation of a blood clot and stabilize it for as long as necessary. Clotting factors are therefore known as procoagulants. Factor I — Fibrinogen; common pathway; converted to fibrin. Factor II — Prothrombin; common pathway; converted to thrombin that converts fibrinogen to fibrin. Factor III — Tissue factor (TF) or thromboplastin; extrinsic pathway. Factor IV — Calcium ions (Ca2+); always present, needed for coagulation. Factor V — Labile factor,...