CONTINUOUS-FLOW SYSTEM FOR THE EVALUATION OF THE EXTRINSIC COAGULATION PATHWAY

A simple and reliable method for the evaluation of the extrinsic coagu lation pathway is presented. The method is based on the monitoring of the last step of the coagulation pathway in which the human plasma is clotted by the presence of the coagulations factors (prothrombin, fact or V, factor X, calcium and phospholipids) in an excess of thromboplas tin. It has been developed using a flow injection system involving the merging-zones and stopped-flow modes. The clotting reaction rate is m onitored photometrically at 340 nm. The linear range expressed as a pe rcentage of total clottable activity was found to be between 10 and 10 0%, with a relative standard deviation between 0.9 and 2.8%. The usefu lness of the method was tested by determining the fibrin clotting capa city in human plasma from healthy and sick individuals with excellent agreement with the conventional clotting method (automated coagulation laboratory-nephelometric method).