FIB is a protein with coagulation function synthesized by the liver. It is factor I of the coagulation factors. When the liver is severely damaged, so that the liver synthesis of fibrinogen function is impaired, the concentration of fibrinogen in plasma is reduced. The following points are summarized for low FIB: (1) Excessive consumption, resulting in reduced plasma levels, such as DIC. (2) Enhanced activity of the fibrinolytic system, with Fg being broken down, as in primary hyperfibrinolysis, etc. (3) Reduced synthesis, e.g. severe hepatitis, cirrhosis, etc. But it is important to note that this is the pathological situation, if only the so-called little bit less and no above these diseases can not be nervous.