Soluble fibrin monomer degradation products as a potentially useful marker for hypercoagulable states with accelerated fibrinolysis

BackgroundFibrin monomer (FM) and its complex (sFC) exist at high concentrations in hypercoagulable state blood. Two novel immunoassays for sFC (SF and FMC) using specific monoclonal antibodies (IF-43 and F405) were recently developed.MethodsWe measured the concentrations of thrombotic markers in 103 patients with DIC and thrombotic disorders.ResultsWe found that the concentration of FMC was approximately 3.35-fold greater than that of SF. In patients with a high FMC/SF ratio, FDP and D dimer concentrations were increased, suggesting that the discrepancy in sFC concentrations was caused by fibrinolytic activity. Further, plasma samples from those patients were found to contain the X- and Y-fragments of FM in addition to FM and sFC in a Western blotting assay using F405, which binds with those fragments. In an in vitro study, FM formed from pooled plasma containing EDTA was degraded to the X- and Y-fragments of FM by fibrinolytic activity, and we termed those FM degradation products (FMDP).ConclusionDetermination of FMDP is important for diagnosis of thrombogenic conditions associated with fibrinolysis, such as in patients with DIC, and it may serve as a useful marker for hypercoagulable states with accelerated fibrinolysis.