Liver function tests are used to monitor various indicators related to liver metabolism through various biochemical experimental methods to reflect the basic status of liver function. There are more than 700 kinds of experiments reflecting liver function, and new experiments are still being developed and established, but they mainly include four major categories: (1) experiments reflecting liver cell damage; (2) experiments reflecting interstitial changes in the liver; (3) experiments reflecting liver reserve function; and (4) experiments reflecting liver excretion function. (1) Experiments reflecting liver cell damage mainly include: serum alanine transaminase (ALT), serum glutamic aminotransferase (AST), alkaline phosphatase (ALP), γ-glutamyl transpeptidase (γ-GT), lactate dehydrogenase and so on. Among them, ALT and AST are sensitive indicators of hepatocellular injury and its degree of damage, reflecting acute hepatocellular injury, ALT is the most sensitive, and reflecting its degree of damage, AST is more sensitive. In the recovery period of re-acute hepatitis, although ALT is normal and γ-GT is persistently elevated, it indicates the chronicity of hepatitis. Chronic hepatitis γ-GT persistently does not drop often indicates lesion activity. An Jingjun, Department of Infectious Diseases, First Affiliated Hospital of Zhengzhou University (2) The main experiments reflecting interstitial changes in the liver are: ① serum protein electrophoresis, now replacing the flocculent reaction, the degree of γ-globulin elevation can evaluate the evolution and prognosis of chronic liver disease, which cannot remove endogenous or enteric antigenic substances from the blood circulation. (2) Serum levels of hyaluronidase (HA), laminin (LN), type III procollagen peptide and type IV collagen reflect changes in hepatic endothelial cells, lipid storage cells and fibroblasts, and are closely related to liver fibrosis and cirrhosis. (3) Tests that reflect the reserve function of the liver are: plasma albumin (ALB) and prothrombin activity (PTA). These two are routine tests that reflect the reserve capacity of the liver by testing its synthesis function. A decrease in albumin indicates a weakened hepatic protein synthesis capacity, and a prolonged PTA indicates a reduced synthesis capacity of various coagulation factors. (4) Experiments reflecting the excretory function of the liver include: detecting the ability of the liver to excrete and remove certain endogenous (bilirubin, bile acids, etc.) or exogenous (dyes, drugs, etc.) high uptake, commonly used in clinical practice to detect the quantification of bilirubin, total bilirubin greater than 17.1μml/liter for jaundice cases, if the bilirubin progressive rise and accompanied by a decline in ALT, suggesting aggravation of the disease, the possibility of turning into severe hepatitis .