A rectal biopsy is a procedure to remove a small piece of rectal tissue for examination.

A rectal biopsy is used to determine the cause of abnormal growths found during anoscopy, sigmoidoscopy, or other tests. It can also be used to confirm the diagnosis of amyloidosis.

A rectal biopsy is usually part of anoscopy or sigmoidoscopy.

A digital rectal exam is done first. Then, a lubricated instrument (anoscope or proctoscope) is placed into the rectum. You will feel some discomfort when this is done.

A biopsy can be taken through any of these instruments.

You may get a laxative, enema, or other preparation before the biopsy so that you can completely empty your bowels.

There will be some discomfort during the procedure, and you may feel an urge to have a bowel movement. Cramping sometimes occurs as the instrument is placed into the rectal area.