Understanding Anorectal Manometry

The rectum and anus let solid waste (stool) leave the body. Anorectal manometry is a test to look at how well the muscles and nerves in these areas are working. It measures pressure in the rectum and anus when you do things during the test like cough, squeeze, and push down.

Why the test is done

This test can help diagnose problems with nerves and the movement of muscles in the anus and rectum. It may be done if a person has any of these problems:

  • Can’t let stool out when needed (constipation)
  • Can’t hold stool in when needed (fecal incontinence)

Risks of anorectal manometry

All procedures have risks. The risks of this test include:

  • Bleeding from the rectum
  • Hole (perforation) in the rectum
  • Pain passing stool after the test
  • Allergic reaction to latex in the balloon

Getting ready for the test

  • Don't eat or drink for 2 hours before the test. If you need to take medicine, take it with a small sip of water.
  • You will likely need to empty stool from the rectum 2 hours before the test. This is done with an enema. You can buy an enema kit at a drugstore. Check which type of enema your provider advised you use. Follow the directions on the package.
  • Tell your healthcare provider about all the medicines you take. This includes over-the-counter medicines. It also includes vitamins, herbs, and other supplements.
  • Tell your healthcare provider if you are sensitive or allergic to latex.
  • Follow all other instructions from your healthcare provider.

What happens during the test

During the test:

  1. You may be given medicine to help you relax.
  2. You’ll lie on your side on a medical table. The healthcare provider will put a thin, flexible tube (catheter) into your anus and rectum. The end of the tube that goes inside the rectum has a small, deflated balloon on the tip. The other end of the catheter is attached to a computer. The tube has pressure sensors on it. The sensors send pressure readings to the computer.
  3. You will be asked to do several things during the test. You will be asked to relax. You will be asked to push down like you are trying to move your bowels. You will be asked to squeeze your anus like you are holding in gas. You may be asked to cough. The healthcare provider will take measurements during each of these actions.
  4. The catheter will be removed. A saline filled balloon may then be inserted. You will be asked to push the balloon and tube out of your rectum like a bowel movement.

After the test

After the test, you can go home. If you had medicine to help you relax, have a family member or friend drive you home. Your healthcare provider will let you know the results of the test.

When to call your healthcare provider

Call your healthcare provider if you have any of these:

  • Fever of 100.4°F ( 38°C) or higher, or as directed by your healthcare provider
  • Pain that gets worse
  • More than a small amount of bleeding from the rectum
  • Signs of an allergic reaction:
    • Itching
    • Hives
    • Trouble breathing ( call 911)
  • Symptoms that don’t get better, or get worse
  • New symptoms