The normal range of total bile acids is 0-9.67 μmol/L (fasting). If the test result is 40 μmol/L, it indicates a possible hepatobiliary system disease and needs to be combined with other liver function tests to clarify the diagnosis. The sensitivity of bile acid measurement is high for the diagnosis of hepatobiliary system diseases. Even when there is only slight damage to hepatocytes, the serum total bile acid concentration can be increased, and its change is earlier than that of bilirubin and ghrelin. Therefore, if the test result is 40 μmol/L total bile acid, it indicates possible acute and chronic hepatitis, cirrhosis, liver cancer and cholestasis. In case of acute or chronic hepatitis, the function of liver cells is impaired, the liver excretion and uptake of bile acids from the portal vein is impaired, and the level of bile acids in the blood will be significantly increased. Studies have shown that the more pronounced the elevation of total serum bile acids, the more severe the damage to liver function. In addition, the increase in total serum bile acids is most pronounced in the presence of extrahepatic biliary obstruction. In cases of cholestatic liver disease (including extrahepatic bile duct obstruction and intrahepatic cholestasis), especially primary biliary cirrhosis and primary sclerosing cholangitis, bile acid reflux into the blood due to obstruction of bile drainage can cause an increase in blood bile acid levels, the degree of which corresponds to the severity of the disease.