Although these assays are useful for determination of titers of alloantibodies against FVIII in congenital hemophilia A patients with type I kinetics, exact determination of autoantibody titer in AHA is difficult in patients with type II kinetics, in whom the acquired inhibitor-FVIII complex may show some residual FVIII:C, even in the presence of high concentrations of inhibitors. The gene discussed is F8; the disease is autoimmune hemolytic anemia.