Formal Urodynamics Test

Formal urodynamics are a group of tests used to study the urinary flow, the bladder and bladder pressures.

The test should not be done if your child has a bladder infection.

  • Explain the test to your child in words he or she can easily understand.
  • One hour before your scheduled testing time, have your child drink according to the following guidelines so that he or she arrives with a full bladder and can urinate for the test. If your child is catheterized at home or is not toilet-trained, it is not necessary to drink extra liquids (continue with your child's catheterization schedule before the test).
    • 3-6 years old: One 8-ounce glass of liquid; no milk or soda pop 
    • 6-12 years: Two 8-ounce glasses of liquid; no milk or soda pop 
    • Adolescents: Three 8-ounce glasses of liquid; no milk or soda pop 
  • Your child may still eat and should take his or her medications. 
  • Your child may ask the nurse any questions before and after the test. 
  • Parents remain in the room during the test. 
  • There are no shots or needles involved in this test.
  • Your child will be asked to change his or her clothes and put on a hospital gown. EMG patches, which look like small square bandages, are placed on the outer thighs and buttocks. These patches are attached to wires that are connected to a computer. They measure your child's muscles but your child will not feel anything. If your child urinates on his or her own, he or she will sit on a portable toilet and be asked to urinate. Boys may stand.
  • After your child urinates, he or she will lie on a bed. Your child's privacy will be maintained through the use of sheets and blankets.
  • The nurse will place a small, thin, soft tube called a catheter in your child's rectum. Then another small, soft catheter will be placed in your child's bladder through the urethra, the tube through which your child urinates. These tubes will stay in place until the study is completed.
  • After the catheters are in place, the bladder is slowly filled with water. Once full, the urethral catheter is removed and your child will be asked to urinate on the portable toilet again. The rectal catheter and EMG patches are then removed.
  • Your child will return to the bed. An ultrasound (diagnostic test using sound waves to get images) of the bladder will be done to measure the amount of urine left in the bladder. A clear, cool gel is put on your child's lower belly for the ultrasound. A picture is made by holding a small object which looks like a microphone on the lower belly.
  • The test is finished. Your child may then wash and redress.
  • Allow 45-60 minutes for the test.
  • Your child's doctor will discuss the test results with you at your child's follow-up appointment.
  • Encourage your child to drink plenty of fluids and avoid caffeine products for 8 hours.

Last Updated 09/2012