Indirect bilirubin is mainly derived from the destruction of red blood cells and is called indirect bilirubin if it has not been glucuronidated in the liver. Indirect bilirubin can be changed to direct bilirubin through hepatic metabolism, which is excreted into the bile duct with bile and finally excreted through the stool. Indirect bilirubin, also known as non-conjugated bilirubin, has a normal reference value of 3.4-17.0 μmol/L. Indirect bilirubin of 15 μmol/L can indicate that it is in the normal range. A low or high clinical indirect bilirubin may indicate a liver lesion. If there is a massive destruction of red blood cells for some reason, the amount of indirect bilirubin produced will increase, and when the liver cannot fully convert it into direct bilirubin, the level of indirect bilirubin in the blood can be significantly increased. When the hepatic synthesis and conversion ability is blocked, indirect bilirubin cannot be converted in a normal and timely manner, which can result in low indirect bilirubin. Indirect bilirubin may also be low when there are fewer senescent red blood cells or when the liver has an increased capacity to process bilirubin. Low indirect bilirubin does not have a greater clinical significance, while increased indirect bilirubin is mainly seen in hemolytic jaundice, hepatocellular jaundice, and cholestatic jaundice. In case of hemolytic jaundice, timely treatment should be provided to avoid adverse complications such as acute renal failure; in case of hepatocellular jaundice, hepatocytes should be protected to avoid further destruction of hepatocytes; in case of cholestatic jaundice, obstruction should be removed in time to unblock the bile duct and protect hepatocytes.