This information is approved and/or reviewed by U-M Health System providers but it is not a tool for self-diagnosis or a substitute for medical treatment. You should speak to your physician or make an appointment to be seen if you have questions or concerns about this information or your medical condition.| Complete disclaimer
Anorectal Manometry (ARM)
Anorectal manometry measures the tone in the anal sphincter and rectal muscles. This test can diagnose problems with defecation (moving your bowels). It can measure:
- resting anal sphincter tone
- releasing anal sphincter tone
- squeezing anal sphincter tone
- muscle coordination
- expulsion of materials
- sensation of the rectum
Who needs anorectal manometry?
People who suffer from constipation or incontinence may be asked to have this test.
How is this test performed?
You will be asked to undress from the waist down and to put on a gown with the opening in the back. A trained technologist will explain everything that will happen. The technologist will ask you to lie on an examination table, turn onto your left side, and bend your knees. A small catheter with a small balloon at the end will be inserted into your rectum. The balloon will be inflated and measurements will be taken while you squeeze and relax your muscles. You will be asked to expel the balloon into the toilet. This test is performed in the GI Physiology Laboratory in the Medical Procedures Unit. The appointment may take up to 1 hour.
Will my insurance cover this test?
Please consult with your ordering physician and health insurance company to insure coverage. NOT ALL INSURANCE COMPANIES COVER THE COST OF THIS TEST. IF WE DO NOT HAVE INSURANCE AUTHORIZATION BEFORE THE TEST, YOU WILL BE RESPONSIBLE FOR PAYMENT.
How do I prepare for this test?
One and a half hours (90 minutes) before leaving home, you will need to perform two 500 cc (about 2 cups) warm tap water enemas. You may purchase the enema bag at a pharmacy or medical supply store. The enema usually takes 15 minutes to work but may take up to an hour. Fill the enema bag with 500 cc (about 2 cups) warm tap water. Do not use hot water. Hang the enema bag on a nail or hook or have someone hold it about 12 to 18 inches above your rectum. Lie on your left side with your knees bent toward your chest. Remove the cap from the enema tip. Gently insert the enema tip about 3 to 4 inches into your rectum. Open the clamp and allow the water to flow slowly into your rectum. The flow rate can be adjusted by moving the clamp. Hold the water in your rectum as long as possible – at least 15 minutes – then expel it into the toilet. Perform the second enema after you have expelled the water from the first one.
How do I get my results?
Your physician will likely correlate these results with other diagnostic tests. A return visit may be scheduled to discuss your results.
Web sites affiliated with the University of Michigan Health System:
Your Digestive System and How It Works
Directions to the Medical Procedures Unit – Look for number 24 on the floor plan.
Instructions for Patients with Diabetes Having Outpatient Tests (on insulin)
Instructions for Patients with Diabetes Having Outpatient Tests (no insulin)