The liver is the largest substantial organ in the human body and is responsible for a variety of physiological functions; once the “liver” machine “strikes” – that is, “liver failure”, people will definitely not “Human”! In order to find out early whether the liver is working properly or not, there are various laboratory tests available in medicine. Unfortunately, there is no one test that can report the full function of the liver, so tests that reflect different aspects of its function are usually combined to evaluate liver function in a comprehensive manner. Among the more than 700 liver function tests, four categories are widely used in clinical practice: serum enzymology The most commonly used tests are glutamate aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), ALT in the hepatocyte plasma, AST in the mitochondria of hepatocytes, and ALP and GGT mainly in the bile duct epithelium. ALT is found in the hepatocyte plasma, AST in the mitochondria of hepatocytes, and ALP and GGT mainly in the bile duct epithelium. All diseases that cause hepatocellular injury, whether they target the liver or are systemic in nature, can be characterized by abnormal elevations of these serum enzymes, especially ALT/AST. Serum albumin (ALB), prealbumin (PA), cholinesterase (CHE), and prothrombin time (PT) all reflect hepatic synthesis and reserve function; a decrease in ALB, which has a half-life of 21 days, suggests a decrease in hepatic synthesis in the last 21 days; PA, CHE, and prothrombin all have short half-lives; a decrease in PA and CHE, and a prolongation of PT, suggest a decrease in hepatic synthesis in the last few hours. The hepatic synthetic function in the last few hours. Hepatic excretory function includes the ability to excrete and remove endogenous bilirubin, bile acids, and exogenous drugs and dyes. Total bilirubin (TBIL) is the sum of direct bilirubin (DBIL) and indirect bilirubin (IBIL), and IBIL is converted to DBIL after binding to specific proteins in hepatocytes. damage to parenchymal cells of the liver may be manifested as hyperbilirubinemia, mainly elevated DBIL; massive erythrocyte lysis will lead to abnormal bilirubin metabolism, mainly elevated IBIL. Indicators of liver fibrosis usually refer to hyaluronic acid, laminin, type III procollagen peptide, and type IV collagen. Stellate cells and fibroblasts in the liver are activated, leading to fibrogenesis in the liver and elevation of the above indicators. Although the above 4 types of tests are commonly used in clinical practice, the functional status of the liver should never be judged on the basis of any one indicator in isolation. The correct diagnosis of the disease must be based on a comprehensive analysis of the medical history, physical examination results and all examination findings.