The strength of the muscles around the anal canal (back passage) and sensation in the anal canal and rectum (lower bowel) may affect how easily and how often you go to the toilet. This may also affect whether you can control your bowels – whether you can hold onto the bowel contents or whether you have accidents or leakage from your back passage.
Your doctor has referred you for anorectal physiology tests because of the bowel symptoms which you are having, and this page tells you about the tests.
Anorectal physiology refers to a set of measurements which examine the way the muscles and nerves around the anal canal are working. As well as taking the measurements, taking a careful history of your symptoms is a key part of the test.
The anorectal physiology test looks at how the anal area functions and may be carried out in addition to other tests (undertaken in other departments) such as endo-anal ultrasound, MR proctogram or transit study. Together, these tests provide the information necessary to help your doctor determine the cause of your symptoms and select the best treatment for them. This will help your doctor to treat you in the best way possible and therefore help to relieve your symptoms.
As with most tests, this test forms one part of the jigsaw of information which your doctor requires in order to treat you. If you do not wish to have the test for any reason, we will simply let your doctor know this. Although it would be useful to have this information, they will continue to treat you as well as possible without it.
Your symptom history and additional tests such as endo-anal ultrasound, MR proctogram or transit study may help the doctor to diagnose your problem. However, these other tests may not give the same information.
No preparation is required for the test, and you do not need to be accompanied to the hospital.
Do not worry if you are menstruating, this will not affect the test. Do not worry if you wear continence pads or if you have not opened your bowels.
You will not be asked to sign a consent form to undergo this test because there is no risk that it can harm you. The test will be explained to you fully when you come to the department, and you will have the chance to ask any questions that you might have. Please do not hesitate to ask questions or voice any worries. If you decide to go ahead with the test, you are confirming that you agree to have the test and understand what it involves.
Before starting the test, a medical history is taken. This will include specific questions about your bowel symptoms, medication or surgery which might affect your bowels, and, if applicable, your childbearing history.
After your history is taken the testing will start. You will be asked to lie on a bed, on your side, with your bottom exposed. The clinician performing the test may be accompanied by another member of staff who will assist and act as a chaperone. Small probes will be inserted into your back passage to take the measurements. Gel is used to make this more comfortable; the probes are no bigger than your little finger and only pass approximately ten centimetres into your bottom. You will be asked to squeeze and use your muscles, cough and to report when you experience particular sensations. You will also have a test to ensure that the sensory nerves around the back passage are working normally and that you can feel normal sensations.
The session usually lasts around half an hour. The test is carried out by an experienced member of staff who will try to make you feel at ease. The test is not painful and so sedation is not necessary. However, you might find the test a little embarrassing, and may experience slight discomfort if you are already sore in that region. If you are already sore please discuss this during your consultation.
We will talk to you about any possible discomfort associated with these tests before starting. Although having a small probe inserted into your back passage may feel uncomfortable and strange, the test cannot cause you any harm. We will try to put you at ease to minimise any embarrassment.
You will be able to travel home and continue with your normal activities immediately after the test.
When the test is completed, you will be given a preliminary indication of the results. The results of the test will then be put into a report with other tests which you may have had and will be reviewed by one of the unit consultants.
A copy will be sent to your referring doctor (or will be available for them on the hospital system) and a copy will also be sent to you and your GP. When you return to see your doctor (for example at the outpatient clinic at UCH or at another hospital) the test results and any appropriate treatment will be discussed with you.
Although this is a specialist test, it is a well-recognised procedure which has been undertaken for many years. Please ask your hospital doctor or GP, or contact the GI Physiology Unit, if you require any further information.
You can also find information at www.
UCLH cannot accept responsibility for information provided by other organisations.
This information page tells you about anorectal physiology but if you have read the page and have any queries please contact the GI Physiology Unit.
Address: GI Physiology Unit Lower Ground Floor, EGA Wing University College Hospital, 25 Grafton Way London, WC1E 6DB
Telephone: 020 3447 9130 (Monday to Friday 09:00 to 17:00)
Switchboard: 0203 456 7890 / 08451 555 000
Email: UCLH.
The GI Physiology Unit is on the lower ground floor of the EGA wing.
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Page last updated: 09 September 2025
Review due: 01 September 2027