Rectal biopsy can be used to determine the cause of blood, mucus, or pus in the stool. Rectal biopsy can also confirm findings of another test or x-rays, or take a biopsy of a growth found in the colon.
Update Date 10/14/2013
Updated by: George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.