There are many aminotransferases in the human body, and there are two main types of aminotransferases that are clinically tested by blood tests for liver function: one is called alanine aminotransferase (ALT); the other is called aspartate aminotransferase (AST); ALT is mainly present in the cell plasma, and AST is mainly present in the mitochondria of the cell plasma. When cells are damaged (such as hepatitis, myocarditis, pancreatitis, etc.), ALT enters the blood first, and when cells are severely damaged and mitochondria are endangered, AST also enters the blood. Since ALT and AST are mainly found in liver cells, when they are significantly elevated, they often indicate liver injury. Of course, there are many causes of liver injury, such as liver trauma, various acute and chronic inflammatory diseases of the liver, fatty liver, cirrhosis and liver cancer. Therefore, it is important not to panic or take it lightly when elevated aminotransferases are found, but to investigate the cause further. The level of “transaminase” can hardly reflect the function of the liver, but transaminase is just a component of liver cells, which is relatively high in liver cells. And at this time, the liver is perfectly capable of working normally if there are not many damaged liver cells. To maintain normal human survival, or normal life activities, about 1/3 of the liver needs to be “working”, so many patients with liver disease are delayed in treatment. What are the common causes of liver damage? 1) Viral hepatitis: These include the common hepatophilic viral infections, namely hepatitis A, B, C, D, and E; and non-hepatophilic viral infections, such as EBV, cytomegalovirus, coxsackievirus, and herpes simplex virus infections. 2) Alcoholism: single heavy alcohol consumption or long-term alcoholism can cause liver loss. 3) Immune disorders: autoimmune hepatitis, primary biliary cirrhosis, autoimmune cholangitis, primary sclerosing cholangitis, etc. are all autoimmune disorders leading to liver damage. 4) Industrial or pharmacological factors: such as long-term exposure to carbon tetrachloride, phosphorus, arsenic, etc. and long-term use of tetracycline, methyldopa, etc. can cause liver damage. 5) Hereditary diseases: hepatocyte necrosis caused by metabolites deposited in the liver due to genetic or congenital enzyme defects, such as hepatomegaly (copper deposition), hemochromatosis (iron deposition) a-antitrypsin deficiency, etc. 6) Metabolic factors: non-alcoholic fatty liver disease caused by overnutrition lack of exercise, mostly associated with metabolic diseases such as diabetes mellitus and coronary heart disease. 7) Bacterial or parasitic infections: bacterial liver abscess, schistosomiasis, amoebic liver abscess, etc. 8) Vascular factors: Buccal syndrome caused by obstruction of the hepatic vein or the inferior vena cava above the outlet of the hepatic vein. 9) Endocrine factors: hyper- and hypothyroidism, diabetes mellitus, etc. can cause liver loss. 10) Tumors: Primary or metastatic tumors of the liver can cause liver damage In addition, serum aminotransferases are also variable in some physiological states, such as strenuous activity, physical exercise, and menstruation, when aminotransferases can also be temporarily elevated. If the cause is not clear through history and non-invasive clinical examination, liver aspiration biopsy can be performed to further clarify the cause.