Urodynamic tests for urinary incontinence are measurements taken to evaluate your bladder's function and efficiency. The actual tests done vary from person to person.

Some urodynamic tests are relatively simple and can be done in a doctor's office; other tests require expensive and sophisticated instruments to measure the amount of pressure experienced by the bladder and urethra.

For basic urodynamic testing:

• You will be instructed to arrive for testing with a full bladder.
• While you urinate into a container, the volume of urine and the rate at which the bladder empties are measured.
• A thin, flexible tube (catheter) is then inserted into the bladder through the urethra, and the volume of any urine remaining in the bladder is measured (post-void residual, or PVR). A slight burning sensation may occur when the catheter is inserted.
• The bladder may be filled with water through the catheter until you have the first urge to urinate. The amount of water in the bladder is measured at this point, and more water may be added while you resist urinating until involuntary urination occurs.

More sophisticated testing uses electrodes placed in the rectum to measure the electrical activity of the muscles while the bladder fills. This test is not commonly done.

Why It Is Done

Urodynamic testing may be done when:

• You have moderate to severe involuntary release of urine.
• Other tests do not determine the cause of incontinence.
• Your doctor suspects there is more than one cause for your incontinence.
• You are considering having surgery.

Results

Normal

The amount of fluid left in the bladder after urinating, when you feel the urge to urinate, and when you can no longer hold back urine are within normal ranges.

Abnormal

One or more of the following may be found:

• More than a normal amount of fluid remains in the bladder after urinating. A large volume of urine remaining in the bladder suggests the flow of urine out of the bladder is partially blocked or the bladder muscle is not contracting properly to force all the urine out (overflow incontinence).
• The bladder contains less fluid or more fluid than is considered normal when the first urge to urinate is felt.
• You are unable to retain urine when the bladder contains less than the normal amount of fluid for most people.

What To Think About

Some people may find it embarrassing to urinate while being observed.

Complete the medical test information form (PDF) (What is a PDF document?) to help you prepare for this test.