Total bilirubin includes direct bilirubin and indirect bilirubin. After the body produces indirect bilirubin, it cannot be excreted in the urine, but must be converted to direct bilirubin by the liver and then excreted from the body. Indirect bilirubin is also known as unconjugated bilirubin and free bilirubin. The causes of high total bilirubin and indirect bilirubin are mostly seen in hemolytic jaundice. Due to the destruction of a large number of red blood cells, the body forms a large amount of indirect bilirubin, which exceeds the uptake, binding and excretion capacity of the liver, resulting in prehepatic jaundice. In addition, the anemia caused by hemolysis, hypoxia and the toxic effect of red blood cell destruction products weaken the hepatocyte’s ability to metabolize bilirubin, causing non-conjugated bilirubin to be retained in the blood beyond its normal reference range, which is manifested as an increase in indirect and total bilirubin, while direct bilirubin is basically normal. At the same time, excessive bilirubin production may also lead to a deepening of the color of the stool in these patients. In addition, high total bilirubin and indirect bilirubin can also be seen in hereditary disorders of bilirubin metabolism, as well as some congenital diseases with reduced bilirubin conversion ability, such as Gilbert’s syndrome, which need to be checked in a specialized hospital.