Hageman Factor Deficiency (Hageman Trait)

Among the congenital disorders of blood clotting, Hageman factor deficiency (HF deficiency, Hageman trait), described by Ratnoff and Colopy in 1955,1is unique: affected individuals have a profound abnormality of clotting, yet they are not bleeders. They come to the attention of a physician not because of a tendency to bleed or bruise excessively, but usually because a routine clotting time is fortuitously found to be prolonged. From this it is evident that HF is not essential for normal hemostasis, although itisessential for the normal clotting of blood in a test tube. The role of HF in blood clotting may be demonstrated in the following manner. Normal plasma exposed to glass markedly accelerates the clotting of normal "intact" plasma, i.e. plasma not previously exposed to glass. This clot-accelerating activity generated in plasma by glass contact has been called Activation Product.2Plasma from subjects with HF deficiency,