a protein that participates in the clotting of blood. It is extracted from donated serum and used in the treatment of the commonest type of haemophilia, in which it is absent
factor VIII in Medicine
factor VIIIn. A factor in the clotting of blood, a deficiency of which is associated with hemophilia A. Also called antihemophilic factor, antihemophilic globulin, antihemophilic globulin A, proserum prothrombin conversion accelerator.