Anorectal manometry

Anorectal manometry is most often done in your health care provider's office or in the outpatient department of a hospital or medical center. This procedure is most often done by a specially trained doctor called a gastroenterologist.

During the test:

• You will be asked to change your clothes and wear a hospital gown for the procedure.
• You will lie on your left side with your knees drawn up toward your chest.
• Before the test, the provider will perform a digital rectal exam to evaluate sphincter tone and pelvic floor function.
• A thin, flexible catheter containing multiple pressure sensors and a small balloon at the tip with a deflated balloon at the end will be inserted gently into your anus and moved up into your rectum.
• The other end of the catheter will be connected to a machine that measures pressure.
• The provider will take pressure readings inside your rectum at different depths. These are called baseline pressure readings.
• Next, the provider will take pressure readings with the balloon inflated to different sizes and in different depths of the rectum.
• You will be asked to squeeze, push, cough, or relax during the above step and your muscle responses will be recorded.
• The pressure of your anal sphincter (the muscle at the end of the rectum that allows stool to pass) will also be measured each time.
• You will be asked if you can feel the balloon at different times and when you feel the urge to have a bowel movement.
• After the test is over, the provider will deflate the balloon, and the catheter and balloon will be removed from your anus.
• The complete procedure takes about 30 minutes.

A balloon expulsion test may also be performed after manometry. A small balloon filled with water is placed in the rectum. You will be asked to expel it while sitting on a commode. Normally, the balloon can be expelled within 1 to 2 minutes.

Preparation usually includes using an enema before the test to empty the rectum. You likely won't need to fast, but you may be told to avoid heavy meals beforehand. Be sure to follow the instructions exactly.

The test does not require anesthesia. When the catheter is inserted, you may feel a little discomfort especially if you have a sore anus or rectum. The catheter and the inflated balloon create the same level of pressure as your stool would.

After the test, there are no restrictions. For example, you may drive home or take public transportation on your own and carry out your routine activities.

Your provider may recommend this test if you have:

• Chronic constipation
• Bowel (fecal) incontinence (not being able to keep stool from passing)
• Obstructed defecation (feeling like stool can't come out)
• Chronic pelvic pain
• Pain while having a bowel movement
• Large intestine (colon) disorders, such as irritable bowel syndrome

This test can also be performed after an injury or surgery to check the function of your anal and rectal muscles.

Normal results mean that your anorectal pressure readings are normal and your anorectal muscles and reflexes function properly.

• The anal muscles function correctly while resting, squeezing, coughing, and pushing.
• The anal muscles relax correctly when you feel the urge to poop.

Abnormal test results may mean any of the following:

• Weak anal muscles or a poor reflex in the rectum, causing fecal incontinence.
• Inability of anal muscles to relax properly when you push, causing chronic constipation.
• Dyssynergic defecation (anismus), a bowel movement disorder, in which the muscles and nerves in the pelvic floor are unable to coordinate to pass stools.
• Hirschsprung's disease, a birth defect in which there is absence of some nerve cells in the large intestine causing problems moving stool.

Anorectal manometry is a safe procedure. Tearing or bleeding of the rectum is a rare possibility. If you are allergic to latex, tell your provider in advance so that latex free balloon can be used. Rarely, patients may experience mild discomfort, bleeding, or lightheadedness during the procedure.

ARM; Anal manometry

Carrington EV, Scott SM, Bharucha A, Mion F, Remes-Troche JM, Malcolm A, Heinrich H, Fox M, Rao SS; International Anorectal Physiology Working Group and the International Working Group for Disorders of Gastrointestinal Motility and Function. Expert consensus document: advances in the evaluation of anorectal function. Nat Rev Gastroenterol Hepatol. 2018 May;15(5):309-323. Epub 2018 Apr 11. PMID: 29636555 pubmed.ncbi.nlm.nih.gov/29636555/.

Rao SSC. Fecal incontinence. In: Chung RT, Rubin DT, Wilcox CM, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 12th ed. Philadelphia, PA: Elsevier; 2026:chap 19.

Wald A, Bharucha AE, Limketkai B, Malcolm A, Remes-Troche JM, Whitehead WE, Zutshi M. ACG clinical guidelines: management of benign anorectal disorders. Am J Gastroenterol. 2021 Oct 1;116(10):1987-2008. PMID: 34618700 pubmed.ncbi.nlm.nih.gov/34618700/.

Updated by: Todd Eisner, MD, Private practice specializing in Gastroenterology in Boca Raton and Delray Beach, Florida at Gastroenterology Consultants of Boca Raton. Affiliate Assistant Professor, Florida Atlantic University School of Medicine. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.