The Urobilinogen urine test measures the level of urobilinogen in the urine. Urobilinogen is a byproduct of the breakdown of bilirubin, a yellowish pigment formed during the normal breakdown of red blood cells in the liver. Normally, a small amount of urobilinogen is present in the urine. Abnormal levels of urobilinogen in the urine can indicate various liver or biliary tract disorders, such as hepatitis, cirrhosis, or obstruction of the bile ducts. This test is often used in conjunction with other liver function tests to help diagnose and monitor liver diseases.