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. Then 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:
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.
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.
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Adam Husney, MD - Family Medicine
Specialist Medical ReviewerAvery L. Seifert, MD - Urology
Current as ofNovember 20, 2015