Direct bilirubin is formed in the intestine by bacterial action as bilirubinogen, which then passes through the hepatic-intestinal circulation, and part of it is excreted in the urine, which is urobilinogen. Most of the urobilinogen is reabsorbed from the intestine, converted into conjugated bilirubin by the liver and then excreted into the intestine. A small portion of urobilinogen is excreted from the glomerular filtration and renal tubules, which is urinary urobilinogen. This is the quantitative test of urinary bilirubinogen with reference values of 0.3-3.55umol/L for men and 0-2.64umol/L for women. Therefore, urobilinogen 3.4 basically falls within the normal range. Qualitative results of urinary bilirubinogen are usually indicated as negative or weakly positive. Compared to the qualitative test, the above-mentioned test can more accurately reflect whether the urobilinogen is normal and the degree of elevation. If the patient has abnormal clinical symptoms and signs, the cause of the disease can be initially determined by urobilinogen, but further blood tests, liver function, and hepatobiliary imaging are needed to clarify the diagnosis. In addition, a normal urobilinogen level cannot exclude the presence of an abnormal disease state, for example, if the urobilinogen is negative in obstructive jaundice, it may also be within the normal range when quantified. This is where symptoms and signs are particularly important in determining the presence of disease.