A protein produced by the liver that plays an important role in the development of blood clots. High levels of fibrinogen in the blood, which are associated with advancing age, obesity, physical inactivity, diabetes, and smoking, appear to raise the risk of cardiovascular disease.
Scientists aren’t certain whether high fibrinogen levels (called hyperfibrinogenemia) are a cause or simply a marker of cardiovascular disease. It’s possible that hyperfibrinogenemia is simply a result of the chronic inflammation that characterizes atherosclerosis, or the buildup of fatty plaques on blood vessel walls that leads to cardiovascular disease. On the other hand, hyperfibrinogenemia may actively increase blood thickness, affect interactions between blood platelets, or trigger other mechanisms that directly promote the formation of atherosclerotic plaques on blood vessel walls.
Doctors measure blood levels of fibrinogen when they suspect blood clotting abnormalities or an inherited fibrinogen abnormality, or, in some cases, to help evaluate a person’s risk of developing cardiovascular disease. The normal range of fibrinogen in the blood is 200-400 mg/dl.
A number of lifestyle changes, such as quitting smoking, losing weight, becoming more physically active, and improving your cholesterol level (lowering LDL, or “bad,” cholesterol and raising HDL, or “good,” cholesterol), may help to lower your fibrinogen level. Even if they don’t, they are of proven benefit in lowering a person’s risk of cardiovascular disease.