Relationship of Platelet Factor 1 and Platelet Fibrinogen to Plasma

¹ From the Department of Laboratories and Division of Hematology, Henry Ford Hospital, Detroit, Michigan

Some platelet factors appear, in the light of our present knowledge, to be characterized by activities similar to those in plasma. These platelet activities may be simply ‘artifacts,’ or a useful and necessary function in the blood coagulation mechanisms may be served by having the activity reside in both plasma and platelets. Two such activities are platelet factor 1 (accelerator) and platelet fibrinogen or clottable factor. The role of platelet factor 1 is somewhat clarified by the fact that a normal prothrombin consumption time was found in the absence of plasma Ac-globulin and platelet factor 1. These same platelets which lacked platelet factor 1 were able to pick up Ac-globulin from normal plasma. In another case, the concentration of platelet fibrinogen appeared to be independent of the concentration of plasma fibrinogen, suggesting that these two types of fibrinogen may have some significant difference.