The normal range of total bilirubin is 3.4-17.1 μmol/L, direct bilirubin is 0-6.8 μmol/L, and indirect bilirubin is 1.7-10.2 μmol/L. Bilirubin is subdivided into total bilirubin, direct bilirubin and indirect bilirubin. The normal range of total bilirubin is 3.4-17.1 μmol/L, direct bilirubin is 0-6.8 μmol/L, and indirect bilirubin is 1.7-10.2 μmol/L. Bilirubin is a product of blood erythrocyte metabolism in the monocyte-macrophage system of the liver, spleen and bone marrow, and is one of the more important indicators of liver function programs. When the patient suffers from liver system diseases or certain physiological factors, it may be manifested as elevated or low bilirubin. If the patient has elevated bilirubin or low bilirubin, it is recommended to go to the hospital in time to identify the cause of the disease and then targeted treatment.