| fibrinase | (n) in the clotting of blood thrombin catalyzes factor XIII into its active form (fibrinase) which causes fibrin to form a stable clot, Syn. factor XIII |
| hageman factor | (n) coagulation factor whose deficiency results in prolongation of clotting time of venous blood, Syn. factor XII |
| plasma thromboplastin antecedent | (n) coagulation factor whose deficiency results in a hemorrhagic tendency, Syn. factor XI |