The 12 liver tests usually reflect whether the liver is damaged or not. The 12 liver tests may vary from hospital to hospital, but they mainly include alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, cholinesterase, total bile acids, albumin, total bilirubin, direct bilirubin, indirect bilirubin, total cholesterol, blood ammonia and other indicators, which can reflect to some extent whether the liver is damaged, the type of damage, the degree of damage and whether the function of the liver is affected. 1. Indicators reflecting damage to liver cells: alanine aminotransferase and aspartate aminotransferase. These two enzymes are extremely sensitive to hepatocyte damage and will increase rapidly when hepatocytes are damaged. Total bilirubin and direct bilirubin are also indicators of liver cell damage. If bilirubin and the first two enzymes are elevated at the same time, it indicates serious liver damage, and the higher the bilirubin, the more serious the condition. If transaminase gradually decreases, bilirubin gradually increases, and the phenomenon of enzyme-bile separation appears, we should be alert to serious liver damage or even liver failure; 2. Indicators reflecting liver excretion function: total bile acid, total bilirubin, direct bilirubin, indirect bilirubin. When the aminotransferase is normal, but the indirect bilirubin is mildly elevated or the direct bilirubin is mildly elevated, it means that the liver has congenital disorders of bilirubin synthesis and excretion or hemolytic diseases, and further examination of related genes and hemolysis is needed; 3. Indicators reflecting liver biliary stasis: γ-glutamyl transferase and alkaline phosphatase. When intrahepatic bile duct damage, advanced hepatocellular carcinoma, bile duct cancer or bile duct stones cause biliary obstruction, resulting in bile stasis, it will cause significant increase of these two enzymes. Elevated gamma-glutamyl transferase alone is seen in fatty liver and early stages of primary biliary cholangitis. Elevated alkaline phosphatase alone, pay attention to bone disease, not necessarily a problem of the liver; 4, indicators reflecting the synthesis of liver function: when the synthetic function of the liver is reduced, it will cause a decrease in albumin, total cholesterol, cholinesterase activity is reduced, cholinesterase has a certain specificity, the more serious liver disease, the lower the value; 5, indicators reflecting the detoxification function of the liver: blood ammonia is the metabolism of amino acids in the body to produce ammonia into the blood after Ammonia is a toxic component that is mainly converted by the liver into non-toxic urea and excreted by the kidneys, when the blood ammonia is elevated, it indicates that the liver detoxification function is impaired. When the above-mentioned indicators are abnormal, further examination is needed to clarify the specific cause of the disease, and then take appropriate treatment measures to address the cause.