Hello and welcome to HCM Urobilinogen is absent in urine under normal circumstances. It is present in urine if there is excess of bilirubin in blood. Bilirubin is of two types: Conjugated and unconjugated. In simple words soluble (conjugated) and insoluble bilirubin (unconjugated). The insoluble or unconjugated bilirubin is not excreted in urine as it is insoluble in water. The soluble pr the conjugated bilirubin appears in urine when there is excess of bilirubin due to various causes. The bilirubin as it passes from the liver to intestine via gall bladder, travels the whole length of the intestine and undergoes some changes there. These changes lead to formation of urobilinogen. The large part of it is converted into urobilin which is present in urine. A smaller part of urobilinogen goes to the large intestine where it is called stercobilinogen and it provides yellow colour to the stools. Urobilinogen is increased if haemolysis is going on in the body. It can also be increased if there is any genetic abnormality affecting the enzymes involved in the metabolism of the urobilinogen. Levels of urobilinogen are very low when there is complete obstruction in the biliary tract. This does not allow the passage of bilirubin to the intestine. I advice you to get your blood bilirubin- total, conjugated and unconjugated done to see if there are any abnormalities in any of these substances. Thanks ans take care Dr Shailja P Wahal