You are asked to void (urinate). The time required to begin voiding and the size, force, and continuity of the urinary stream is recorded. The amount of urine, how long the voiding took, and the presence of straining, hesitancy, and dribbling are also recorded.

You lie down, and a catheter (a thin, flexible tube) is gently positioned in the bladder, and any urine left in the bladder is measured and recorded. A catheter is then placed in the rectum and measuring electrodes are placed in the perineum (area near the rectum).

Next, the thermal sensation is evaluated. Room-temperature saline solution is instilled into the bladder, followed by warm water.

You will tell the health care provider what, if any, sensations are felt. The water is then drained from the bladder.

A cystometer (a tube used to monitor bladder pressure) is connected to the catheter. Water or carbon dioxide gas is slowly introduced into the bladder at a controlled rate.

You will tell the provider when you first feel the need to urinate. The pressures and volumes are recorded. When the bladder is full, you must urinate, and the pressure of the urination is recorded.

The bladder is again drained of any residual urine and the catheter is removed.

No special preparations are necessary for this test.

Infants and children:

The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust. For general information regarding how you can prepare your child, see the following topics:

• Preschooler test or procedure preparation (3 to 6 years)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)

There is some discomfort associated with this test. You may experience pain, flushing, sweating, nausea, bladder filling, and a sense of an urgent need to urinate.

The test will help determine the cause of bladder-voiding dysfunction.

Normal values vary and should be discussed with your health care provider.

The test might indicate a cause for urinary tract infection, diminished bladder capacity, multiple sclerosis, stroke, a spinal cord injury, bladder outlet obstruction, or overactive bladder.

There is a slight risk of urinary tract infection and blood in the urine.

This test should not be done if you have a known urinary tract infection. An existing infection increases the possibility of false test results, and the test increases the possibility of spreading of the infection.