Plasma fibrinogen, also known as coagulation factor I, is involved in the common coagulation process of the exogenous and endogenous coagulation pathways, with a normal value of 2-4 g/L. Increased fibrinogen is commonly seen in diabetes, acute myocardial infarction, acute infectious diseases (such as epidemic hemorrhagic fever), rheumatic diseases, acute glomerulonephritis, nephrotic syndrome, burns, multiple myeloma, shock, post major surgery, hypertensive syndrome of pregnancy, acute infection, malignancy, and prethrombotic states, and high fibrinogen concentrations in some older adults. Hypofibrinogen is seen in patients with diffuse intravascular coagulation, primary fibrinolysis, severe hepatitis, and cirrhosis.