A rectal biopsy is a procedure to remove a small piece of tissue from the rectum for examination.
How the Test is Performed
A rectal biopsy is usually part of anoscopy or sigmoidoscopy. These are procedures to view inside the rectum.
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.
How to Prepare for the Test
You may get a laxative, enema, or other preparation before the biopsy so that you can completely empty your bowel. This will allow the doctor a clear view of the rectum.
How the Test will Feel
There will be some discomfort during the procedure. You may feel like you need to have a bowel movement. You may feel cramping or mild discomfort as the instrument is placed into the rectal area. You may feel a pinch when a biopsy is taken.
Why the Test is Performed
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 .
Normal Results
The anus and rectum appear normal in size, color, and shape. There should be no evidence of:
- Bleeding
- Polyps
- Hemorrhoids
- Other abnormalities
No problems are seen when the biopsy tissue is examined under a microscope.
What Abnormal Results Mean
This test is a common way to determine the specific causes of abnormal conditions of the rectum, such as:
- Abscesses
- Colorectal polyps
- Infection
- Inflammation
- Tumors
- Amyloidosis
- Crohn disease
- Hirschsprung disease in infants
- Ulcerative colitis
Risks
Risks of a rectal biopsy include bleeding and tearing.



