DIGESTIVE DISEASE CENTER | Gastroenterology home | Surgery home

Patient care — diagnostic tools, tests, procedures

Anal or rectum biopsy can be used to determine the cause of blood, mucus, or pus in the stool. Anal biopsy can also confirm findings of another test or X-rays, or take a biopsy of a growth found in the colon. A rectal biopsy is used to determine the cause of abnormal growths found on anoscopy, sigmoidoscopy, or other tests. It can also be used to confirm the diagnosis of amyloidosis.

How the test is performed: A rectal biopsy is usually part of anoscopy or sigmoidoscopy.

First, a digital rectal examination is performed. The doctor inserts a lubricated, gloved finger into the rectum to determine if anything will block the insertion of the anoscope.

A lubricated anoscope (or sometimes, a rectal speculum or proctoscope) is then inserted, which will cause some pressure. If a biopsy must be taken, it can be done through any of these scopes. The scope is a short tube with a light attached; it enlarges the rectum to allow the doctor to view the entire anal canal. Anesthetic is introduced through the anoscope, then biopsy forceps, a cytology brush, culture swab, or suction catheter is introduced through the anoscope to take a sample. Afterward, the scope is slowly removed.

illustration

Return to diagnostic tests, tools page