Measurement of fibrinogen degradation products by a sandwich enzyme immunoassay technique.

We describe a highly sensitive enzyme immunoassay technique using beta-D-galactosidase from Escherichia coli as a label to quantify fibrinogen and its degradation products. The minimum detectable concentrations of fibrinogen, fragment D and fragment E, were 0.6, 0.06 and 0.2 ng/ml of reaction mixture, respectively. The cross-reactions of the assay-system for fragment E with fibrinogen and fragments X, Y and D were 5, 8, 56 and 0% respectively. The assay system for fragment D did not cross-react with fragment E, but did cross-react with fragments X, Y and fibrinogen (38, 10 and 15% respectively). Fractionation of the serum sample on Sephadex G-200 column allowed specific quantification of fragments D and E in serum samples.