The cystometric study uses a device to pump water into the bladder. The device then measures the amount of fluid that goes into the bladder when you first feel the desire to void, when you are able to sense fullness, and when your bladder is completely full.

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 are then asked to lie down. A catheter (a thin, flexible tube) is gently positioned in the bladder, and any urine left in the bladder is measured and recorded. Next, the thermal sensation is evaluated. Room temperature saline solution is instilled into the bladder, followed by warm water.

You need to 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 need to tell when the need to void is felt. The pressures and volumes are recorded. When the bladder is full, you must void, and the pressure of the voiding is recorded. The bladder is again drained of any residual urine and the catheter is then removed.

• 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)

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