Bile (mainly conjugated bilirubin) is converted to urobilinogen by intestinal bacteria. Most of the urobilinogen is excreted in faeces or reabsorbed and transported back to the liver to be reconverted into bile. The remaining urobilinogen (about 1% of total) is excreted in the urine.
This is a companion discussion topic for the original article at https://patient.info/doctor/investigations/bilirubinuria