ABSTRACT
Blood contains a variety of plasminogen activators (PA). Classically their assay has involved dilution of whole blood or euglobulin precipitation of plasma, procedures designed to remove plasma inhibitors of fibrinolysis. 1 Assays are usually performed on plasma, although blood cells make a significant contribution to the lytic activity of blood as a result of platelet-induced clot retraction 2 and leukocyte release of neutral proteases. 3 While the latter is dependent on metal ions and is not inhibited by amino-caproic acid, implying plasminogen independent clot lysis, enhanced cellular activity has been found, e.g., after exercise 4 or aspirin ingestion, 5 and may thus have a role in the modulation of fibrinolytic activity.
