Urine bilirubin results are an important clinical reference in determining hepatobiliary disease and identifying the type of jaundice. It is helpful to understand the causes of elevated urine bilirubin. First, let’s understand how urine bilirubin is formed. After aging, red blood cells in the body are broken down and destroyed by the monocyte-phagocyte system, and bilirubin is formed through a series of reactions. Bilirubin is combined with albumin in the blood and transported to the liver, where it is combined with glucuronic acid through a series of chemical reactions to form conjugated bilirubin, which can pass through various biological membranes in the body, including the glomerular filtration membrane. Normal urine contains a small amount of bilirubin, which cannot be detected by the usual examination methods. When the concentration of conjugated bilirubin in the blood increases beyond the threshold that the kidneys can tolerate, the conjugated bilirubin will be excreted through the urine by filtration by the kidneys, causing an increase in the level of bilirubin in the urine. Obviously, as long as the factors that can cause the increase of conjugated bilirubin in the blood can cause the increase of urinary bilirubin. The causes are summarized as follows: 1) obstruction of bile discharge: such as gallstones, bile duct tumors, pancreatic head cancer and other obstructions caused by compression of bile ducts, resulting in obstruction of bile discharge and excessive conjugated bilirubin entering the blood; 2) liver cell damage: such as viral hepatitis, drug-induced hepatitis, alcoholic hepatitis and other causes of conjugated bilirubin can not be discharged into the blood in a timely manner; 3) alkalosis in the body will cause an increase in bilirubin secretion and excessive bilirubin will be discharged through the blood circulation. The excessive bilirubin is filtered through the kidney with blood circulation, which will also cause the increase of urinary bilirubin.