Plasma D-dimer levels and their relationship to serum fibrinogen/fibrin degradation products in hypercoagulable states

Plasma D-dimer was measured and compared with serum fibrinogen/fibrin degradation product levels (FDPs) in patients with disseminated intravascular coagulation (DIC) and other conditions associated with a hypercoagulable state. D-dimer (N less than 200 ng/ml) was elevated in all 43 patients with DIC, in 48 of 59 patients with liver disease, in 22 of 27 patients with acute leukaemia at presentation, in 17 of 23 patients with malignant disease, in 29 of 39 women in the third trimester of a complicated pregnancy, in 17 of 18 patients with deep venous thrombosis and in only four of 27 patients with acute myocardial infarction. There was a significant correlation between plasma D-dimer and serum FDP levels (P less than 0.01) as follows; DIC: r = 0.58, liver disease: r = 0.57, acute leukaemia: r = 0.84, malignancy: r = 0.87. The frequent elevation of D-dimer observed in liver disease, acute leukaemia, malignancy and complicated pregnancy indicates that a hypercoagulable state is a common occurrence in these conditions although in liver disease elevated levels resulting from a failure of normal clearance mechanisms cannot be excluded. The close relationship between D-dimer and FDP levels suggests that serum FDPs predominantly arise from the interaction of plasmin with crosslinked fibrin rather than with fibrinogen in the conditions in which these were compared.