Often liver function is also a routine part of a physical examination. Testing for normal liver function is especially important for people who are old and frail and often take medication, as medication can sometimes damage the liver and kidneys. Preparation for the liver function test: Fasting is usually 8-12 hours before the blood is drawn, usually after 8:00 p.m. the night before the blood is drawn and no food or water after 12:00 p.m. This is especially true for first-time liver function tests. Three days before the blood test, it is best to stop taking drugs that are harmful to the liver, and to take rest and not to work hard or stay up late. It is best to abstain from alcohol and eat a light diet the day before to avoid affecting the results of the liver function test. Interpretation of liver function indexes? 1.hepatocyte damage examination: generally serum enzyme test, the project generally has glutamic aminotransferase, glutamic oxalacetic aminotransferase, alkaline phosphatase (ACP), γ-glutamyl transpeptidase (γ-GT) and so on. Aminotransferases are items of common concern and prone to fluctuations, such as glutamate aminotransferase (also known as glutamate aminotransferase, or GPT or ALT) and glutamic oxaloacetic aminotransferase (also known as menthyltransferase, or GOT or AST). Glutamate aminotransferase is mainly distributed in the hepatocyte plasma and glutathione aminotransferase is mainly distributed in the hepatocyte plasma and mitochondria of hepatocytes. When inflammation or necrosis occurs in damaged hepatocytes, GOT and AST will be elevated, and the degree of elevation corresponds to the degree of hepatocyte damage, so it is by far the most commonly used indicator of liver function. In addition to inflammation, liver cell damage can also be caused by alcoholism, drugs, etc. Therefore, you should abstain from alcohol and use drugs carefully before the blood test. 2.Liver excretion function test: to detect the liver’s ability to excrete and remove certain substances, items such as bilirubin and bile acids. Every day, a certain number of red blood cells are destroyed or die naturally in the blood, and these red blood cells are able to release indirect bilirubin. The normal liver converts this indirect bilirubin into direct bilirubin, which is excreted into the digestive tract via the bile and eventually out of the body. If the bilirubin is not excreted properly, it will cause “jaundice”, which is characterized by yellow eyes, yellow urine and yellow skin. In addition to liver damage, excessive destruction of red blood cells and impaired excretion of direct bilirubin can also cause high bilirubin in liver function tests. In general, elevated direct bilirubin and indirect bilirubin at the same time is common in liver diseases; and when elevated direct bilirubin is the main cause, it may indicate bile duct obstruction. 3, liver storage function test: the liver synthesis function is tested to reflect its storage capacity, the items are generally plasma albumin (ALB), globulin (GLB), albumin/globulin ratio (A/G), etc.. In severe hepatitis, albumin can be significantly lower and is directly proportional to the severity of the disease. When serum albumin is less than 30 g/L it is a sign of poor prognosis and a sign of liver failure, such as low albumin in the late stages of cirrhosis. Inflammatory stimulation of the liver usually results in an increase in globulin synthesis, which can be transiently elevated in acute hepatitis and then fall to normal after recovery, if the globulin continues to be elevated indicating chronic hepatitis. In chronic hepatitis, albumin is normal, but globulin is elevated, so the ratio decreases; in cirrhosis and severe hepatitis, the ratio decreases significantly or even inverts because albumin synthesis decreases while globulin synthesis increases. Warm tip: liver function test can only be used as an auxiliary means to diagnose hepatobiliary system diseases, to make a correct judgment of the disease, it must be combined with medical history, physical examination and imaging examinations, etc. Comprehensive analysis, so once the test index deviates from the normal value, other tests should be done under the guidance of the doctor to confirm the diagnosis of the disease and early treatment.