A rapid and highly sensitive solid-phase radioassay for plasminogen activators.

A rapid and highly sensitive solid-phase radioassay for the measurement of plasminogen activators is presented. The method employs a convenient and stable 125I-fibrinogen-latex bead product and can reproducibly detect 0.25 milli Ploug units/ml of urokinase. This represents a 100-fold increase in sensitivity over previously published radioisotopic solid-phase technique and a 120-fold increase over the sensitivity of the fibrin plate method. Since the assay can readily detect plasminogen activator levels in euglobulin solutions prepared from pre- and post-venous occlusion plasma, it may be useful for rapidly detecting and monitoring the fibrinolytic potential of patients predisposed to thromboembolic disease.