Immunoephelometric determination of fibrinogen and its derivatives in plasma

An immunonephelometric method for determination of fibrinogen and fibrin degradation products in plasma is described. Test plasms are diluted 1/600 in a solution containing 17 g NaCl and 3.8 g trisodium citrate/100 ml. To 3 cm 3 of this mixture 0.2 cm 3 of a concentrated antifibrin gamma globulin preparation is added. The reading of this sample minus the γ-globulin blank in a Thorp Nephelometer is directly proportional to the fibrinogen content of the plasma or to its FDP concentration in terms of intact fibrinogen. This paper examines the mechanism, accuracy and reproducibility of this method.