A Study of Fibrinogen Turnover in Classical Hemophilia and Congenital Afibrinogenemia

The rate of disappearance from the plasma of intravenously administered I¹³¹-labeled fibrinogen was studied in six patients with classical hemophilia and in one patient with congenital afibrinogenemia.

The six patients with hemophilia had radioiodinated fibrinogen half-lives ranging from 2.8 to 3.6 days, while the patient with congenital afibrinogenemia had a labeled fibrinogen half-life of 3.0 days. These results compare favorably with fibrinogen turnover rates measured in normal adults by others and were similar to the normal fibrinogen turnover rate determined in the patient with congenital afibrinogenemia in a previous study. This failure to demonstrate a prolongation of survival of fibrinogen in patients with hemophilia suggests that in vivo clotting, if it occurs at all normally, is not a major factor in the turnover of fibrinogen.