New plasma assays for fibrin(ogen) degradation products have become available which are based upon monoclonal antibodies and can be performed in plasma. In this study we have evaluated four of such specific enzyme immuno assays i.e.: for the total of degradation products of fibrin and of fibrinogen (TDP), fibrin degradation products (D-dimer and FbDP) and fibrinogen degradation products (FgDP) in patients suspected of having deep venous thrombosis of the leg (DVT) and patients with cirrhosis of the liver. DVT was assessed by impedance plethysmography (IPG). In each of the (sub) groups of patients, a very good correlation (0.90 less than r less than 0.98) was observed between the actually measured TDP values and the calculated sum of the separately measured FbDP and FgDP levels. Only 2% (5 patients) of the cases showed a discrepancy of more than a factor two between the found TDP values and the calculated sum of the measured FbDP and FgDP levels. About 90% of the fibrin degradation products were crosslinked. FbDP levels correlated well with the FgDP levels (0.72 less than r less than 0.94) and D-dimer levels (0.82 less than r less than 0.91) in both patients with DVT and cirrhotics. In those patients also a good correlation (0.67 less than r less than 0.83) was observed between FgDP and D-dimer levels, but not in patients suspected of having DVT but with a normal IPG test result. Secondary fibrinolysis appeared to be accompanied by fibrinogenolysis.