urobilin
Last reviewed 01/2018
Urobilin is a bile pigment derived from bilirubin via the intermediate urobilinogen. It is water soluble and imparts a brown colour to faeces.
Urobilinogen is formed:
- by partial oxidation of urobilinogen during transit along the bowel
- by oxidation within urine of urobilinogen
Hence, urobilin is found within both faeces and urine. Urinary losses may be up to 5mg/day in a healthy adult.