Measurement of crosslinked fibrin degradation products - an immunoassay using monoclonal antibodies.

We have prepared a monoclonal antibody which recognises an antigenic determinant on D dimer, a specific fragment resulting from the degradation of crosslinked fibrin. This antibody has been used in the development of an enzyme-linked immunoassay for D dimer and related degradation products containing crosslinked gamma-gamma chains, to provide a simple assay of circulating crosslinked fibrin degradation products suitable for clinical use. Since these crosslinked fibrin degradation products are characteristic of fibrinolysis, as distinct from fibrinogenolysis, their measurement should aid in the diagnosis, evaluation and monitoring of thrombotic and thrombolytic states. In preliminary studies, low concentrations of crosslinked fibrin derivatives were detected in normal sera. High levels were found in 30/30 patients with disseminated intravascular coagulation and in the majority of patients having deep venous thrombosis or pulmonary embolism.