Flow Rate Test

What is a flow rate test?

A flow rate test assesses how your child urinates (pees or voids). It is not invasive and does not hurt.

Your child will be asked to urinate into a flow rate toilet. This is a special toilet that measures the volume (amount) and rate (speed) of urine flow. The nurse will explain this test to you and your child as it is being performed.

Before and after the test, a bladder scan is done to show how much urine is left in your child's bladder (residual urine).

What is a flow rate test with EMG?

A flow rate test with EMG is similar to a regular flow rate test. EMG is a test that looks at how muscles and nerves work together. Your child will have electrodes, which are like stickers, gently placed on the buttocks and hip. These electrodes allow us to assess your child's pelvic floor muscles while your child pees.

Purpose of the flow rate test

Your child may be sent for this test for any of the following reasons:

  • to see if your child has urination problems
  • to assess the effects of certain medicines
  • to evaluate how your child urinates before and after an operation
  • to assess the results of a procedure

Getting ready for the test

Your child will need a full bladder for this test.

Remember that it takes 20 to 30 minutes for liquid to get down to the bladder. If your child does not normally drink a lot of water, or if your child has been ill, your child may be slightly dehydrated. If your child is dehydrated, it will take more water to fill the bladder.

Your child can eat and drink as usual before this test. You can bring his or her favourite drinks or formula from home or buy a drink from the hospital cafeteria.  

Taking the test

Every child has a different bladder capacity. We want to do this test when your child feels a strong urge to urinate. A strong urge to urinate shows that your child's bladder is full.

If your child is not ready for the test when you arrive at the clinic, encourage your child to drink water. When your child feels a strong urge to urinate, please tell the clerical staff at the front desk.

Once your child's bladder is full, the test will take about 5 minutes. Your child will have a bladder scan and will be asked to urinate into the flow rate toilet. Then your child will have a second bladder scan to see if any urine is left in the bladder.  

Test results

A doctor or nurse practitioner in the Urology Clinic will review the test results. If your family physician or paediatrician has sent your child for this test, the results will be forwarded to them.

If you have questions, speak with your urologist, nurse practitioner, or urodynamics nurse.

Key points

  • A flow rate test assesses how your child urinates (pees). Your child will need to urinate into a special toilet.
  • Your child will need a full bladder for the test.
  • Your child will have a bladder scan before and after urinating.

Cathy Daniels, RN (EC), MS,  NP-Paeds


At SickKids:

If this is your child's first visit to the hospital, you will need to register at Clinic Registration on the main floor, in the Atrium. Then go to the Urodynamics clinic on 5D (Atrium elevators), where the test is done.

If your child has been to the hospital before, go directly to 5D.

Check in with the clerical staff at the front desk of 5D. You can wait in the kitchen or playroom on 5D until your child is ready for the test.

If you have any questions, speak with your urologist or nurse practitioner or call the urodynamics nurses at 416-813-6661.

For any cancellations or changes in appointment dates, please call the Urology Clinic at 416-813-6661.