Fibrinogen, a soluble plasma protein, is a cofactor in platelet activation. It is converted to fibrin in a reaction catalyzed by thrombin. Fibrinogen is a major determinant of plasma viscosity. It has been demonstrated to be an independent risk factor of cardiovascular disease. Some studies indicate an association between fibrinogen plasma level and the subsequent development of all the major atherosclerotic cardiovascular events, including coronary artery disease, stroke, and myocardial infarction.