Fibrin D-dimer in thrombogenic disorders

Measurement of D-dimer (fibrin degradation product) is important for determ ining not only the activation of fibrinolysis but also the severity of a hy percoagulable state. However, fibrin degradation products are in variable, and the reactivity to cross-linked fibrin degradation products produced dur ing fibrin degradation differs depending on the kind of antibody used again st D-dimer. In patients with disseminated intravascular coagulation or eart hquake-induced mental and physical stress and in patients after percutaneou s transluminal coronary angioplasty, all of which are associated with acute fibrin formation and degradation, some discrepancies between two methods o f D-dimer detection, automated latex agglutination assay (LPIA) and enzyme- linked immunosorbent assay (Stago), were found. No discrepancies in persist ent fibrin formation and degradation were found among the healthy elderly, patients with lacunar stroke, and patients with coronary artery disease, al most all of whom had levels under 5.0 mu g/mL, as determined by both method s. Evidence of persistently increased intravascular coagulation and fibrin turnover in patients with atherosclerotic disease was found. The cleavage o f crosslinked fibrin by plasmin results in a production of fibrin degradati on products, mostly contained D-dimer domains. Although the clinical utilit y of D-dimer can be achieved by their detection with specific antibodies, m easurement of D-dimer as high-molecular-weight fragments may be useful to d etermine whether patients will undergo further fibrin degradation. When int ermediate products of the degradation process need to be assessed, D-dimer level measurement by LPIA may serve as a suitable marker for ongoing fibrin olysis.