Verified
Clotting factors are substances (that is, reagents, enzymes and coenzymes,) essential for the clotting phases to happen. Besides such triggering factors and reagents already explained (tissue and platelet factors, prothrombin, thromplastinogen, fibrinogen and calcium ions), other substances contribute in the blood clotting process as clotting factors, such as factor VIII, whose scarcity causes hemophilia A, or the factor IX, whose deficiency causes hemophilia B.