Summary
Fibrin(ogen) degradation products (FDP) are detected by radioimmunoassay in the serum of all subjects. Some of these FDPs have considerable biological activity in vivo, and hence may play a significant part in the process of coagulation. Chromatography of serum samples from patients including those with pulmonary emboli and deep venous thrombosis indicates that the majority of non-clottable fibrin(ogen)-related antigen present is of high molecular weight- greater than that of fibrinogen – and that in pathological situations there is a quantitative increase not a qualitative alteration in the molecular species present.