Urodynamic Tests

Why It Is Done

These tests are done to help find out why a person has symptoms such as:

• Leaking urine.
• Feeling the need to urinate often.
• Pain when urinating.
• A weak stream of urine.
• Not being able to urinate.
• Frequent urinary tract infections.

How To Prepare

You may be asked to arrive for the test with a full bladder. Tell your doctor if you have symptoms of a urinary tract infection the day of the test.

How It is Done

For basic urodynamic testing:

• You will urinate into a container while the amount of urine and how fast it flows out of the bladder are measured.
• A thin, flexible tube called a catheter is then inserted into the bladder through the urethra. The urethra is the tube that carries urine from the bladder to the outside of the body. This catheter helps measure the amount of urine still in the bladder and the pressure in your bladder.
• Another catheter may be placed in your rectum to measure the pressure in your abdomen as your bladder fills.
• 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 you no longer can keep from urinating.
• The doctor will remove the catheter.
• Sometimes X-rays are taken during a test. If they are, your bladder may be filled with fluid that will show up on an X-ray.

How long the test takes

How long the test will take depends on the type of test you have. Ask your doctor how long your specific test or tests should take.

How It Feels

You may feel a slight burning sensation when the catheter is inserted. You may feel uncomfortable as your bladder is filled with water.

Results

Normal

One or more of the following are within normal ranges:

• The amount of fluid left in the bladder after you urinate.
• The amount of fluid in the bladder when you feel the urge to urinate.
• The amount of urine that can be stored in your bladder.
• The amount of fluid left in your bladder when you can no longer hold back urine.

Abnormal

One or more of the following may be found:

• More than a normal amount of fluid remains in the bladder after you urinate. A large volume of urine remaining in the bladder suggests that 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.
• 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.
• You are unable to urinate.
• You leak urine when you cough or when you strain (Valsalva maneuvers).