Urinary bilirubin is a substance that is eliminated from the body as a result of aging and destruction of abnormal red blood cells, and is excreted in the form of urine after being broken down by the liver and combined with glucuronide and filtered by the glomerular membrane. Under normal circumstances, the urine bilirubin test is negative. An elevated bilirubin level in the urine indicates the presence of certain diseases, such as viral hepatitis, hepatocellular liver cancer and gallbladder stones. Firstly, the liver is an important place for metabolizing bilirubin in the body, and once pathological changes occur, a large amount of bilirubin that cannot be metabolized in time will enter the blood, urinary tissues, mucous membranes and other systems, resulting in an abnormally high level of bilirubin in the urine. Secondly, bilirubin is also widely present in organs and tissues such as duodenum, pancreas and gallbladder, and when these organs and tissues become diseased, the direct bilirubin excretion channels will be blocked, causing the bilirubin level in urine, blood and other body fluids to increase.