urobilin

Urobilin is a yellow-orange pigment that results when the body breaks down older red blood cells. Hemoglobin, the molecule in red blood cells that carries oxygen, is processed in the liver and eventually broken down into several components, including bilirubin. Bilirubin is then processed further and converted into urobilin, which gives urine its characteristic yellow color. Essentially, urobilin is a waste product excreted in urine, indicating normal processing and disposal of red blood cell components. Its presence and concentration can be useful in medical tests to assess liver function and overall health.