Definition of Rectal biopsy:

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

How the test is performed:

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.

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 bowels. This will allow the doctor a clear view of the rectum.

How the test will feel:

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

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 Values:

The anus and rectum appear normal in size, color, and shape. There should be no evidence of bleeding, polyps, hemorrhoids, or other abnormalities. When biopsy tissue is examined under a microscope, no abnormalities should be noted.

What abnormal results mean:

This test is a common way to confirm amyloidosis. It also determines the specific causes of abnormal conditions of the rectum, such as colitis. Other findings could include:

• Abscesses
• Colorectal polyps
• Infection
• Inflammation
• Tumors

The test may be also performed for:

• Crohn's disease
• Hirschsprung's disease in infants
• Ulcerative colitis

What the risks are:

There is some risk of bleeding and tearing. Occasionally, patients may develop difficulty with urination after the procedure.