What are urodynamic tests for urinary incontinence?

Urodynamic tests check the function of the bladder. They determine whether or not the relationship between pressure and volume in the bladder is normal as it fills and if the flow rate is normal as the bladder empties. It is a sophisticated way to reproduce bladder symptoms and to pinpoint specific problems.

Many doctors who diagnose patients with urinary problems have a urodynamic testing lab outfitted with a special chair and computer equipment that can help obtain measurements of urinary pressure and flow. If your condition is not easily diagnosed by a physical exam and a discussion of your symptoms, or if the strategy your doctor recommends does not improve your incontinence, your doctor may suggest urodynamic testing to administer a series of specialized tests that help evaluate your urinary system in action. It is available for both men and women.

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.