Comparison of the specificity of four fibrinogen assays during thrombolytic therapy

Abstract

Three functional assays for fibrinogen were compared with an ELISA method which, as a result of the use of two monoclonal antibodies, one reacting with N- and the other with C-terminal domains of the Aα chain, only detects fibrinogen molecules with at least one intact Aα chain. In normal plasma and plasma from patients not receiving thrombolysic therapy, all four methods showed excellent correlations. In the presence of high levels of fibrinogen degradation products (FgDP), however, there was very poor agreement between the methods. Two clotting assays (Clauss and Blombäck methods) were negatively interfered by FgDP and the ACL nephelometric method positively. Therefore, the degradation of fibrinogen during thorombolytic therapy with (pro-)urokinase proved much less extensive than expected from previous studies. The well-documented fibrinogen rebound 48–72 hours after thrombolysis was not observed using the ELISA for intact fibrinogen.