Fibrinogen is an important coagulation factor which is synthesized in the liver.
Thrombin converts fibrinogen to fibrin monomers leading to spontaneous fibrin polymerization. The fibrin polymers form a fibrin clot, together with platelets. Fibrin polymers are digested by the fibrinolytic system. Elevated levels of fibrinogen have been observed during acute - phase reactions, pregnancy and oral contraception , menopause, smoking, malignancies or chronic inflammatory diseases. Increased fibrinogen concentrations have been associated with thromboembolic states and are considered as risk factors for thrombotic disease. Low fibrinogen concentrations can occur during acute or chronic liver disease, disseminated intravascular coagulation, thrombolytic therapy, hemodilution and during consumption coagulopathy. Chronically low levels may be also related to inherited conditions such as afibrinogenemia or dysfibrinogenemia.
Fibrinogen levels are usually determined for pre‑operative screening or in case of unexplained prolonged bleeding.