Fibrin is a protein with coagulation function in the body and is generally synthesized by the liver. When the liver is impaired or has other liver diseases, resulting in liver insufficiency, the fibrin in the body will be low. This condition is usually caused by the liver synthesis fibrinogen dysfunction, resulting in a decrease in the concentration of fibrinogen in the blood plasma, which will affect the blood clotting function in the body, further causing patients to bleed easily and the possibility of subcutaneous petechiae and petechiae. Another condition is that the patient may have primary and secondary hyperfibrinolysis, causing hypofibrinogenemia. Further testing is needed to see if the patient has any acute inflammatory or septic conditions that could be causing hyperfibrinolysis. In the case of low fibrinogen in the liver, the patient needs to be actively blood tested for hepatitis B and C. If necessary, hepatitis B DNA and hepatitis C RNA need to be checked, which may be due to viral replication, combined with impairment of the patient’s liver function, further causing low fibrinogen.