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Renal GFR Scan

A Renal Scan & GFR (Glomerular Filtration Rate) tests how well your child's kidneys work and how blood flows through them.


The scan has several parts and will take about three hours to complete. There will be breaks in between where you and your child can leave the department.  One parent or guardian must always stay with the child during the scan.  Siblings are not allowed in the room during the test.  Eating and drinking are not allowed in the room.

Your child can eat and drink as usual. It helps to give your child something to drink (for example, juice or water) before you arrive for the test.  Your child may be asked to stop certain medications the morning of the test, specifically diuretics (for example, Lasix).

What to expect

Part 1

Your child will need Intravenous (IV) access for this procedure.  An IV is a needle that is inseted into a vein, most often in the arm or back of the hand. An injection with a small amount of radioactive medicine will be given through the IV. This medicine will allow us to take pictures of your child’s kidneys to see how they are working. 

Your child will lie down on a narrow bed and a seat belt will be placed across their body for saftey and to help them remain still for pictures. Your child should not feel any discomfort during the scan and can choose to be distracted (for example, watch a movie). 

The pictures will take about 30 minutes to complete. Your child can leave the department after the pictures are done and you will be told what time to return for the second part of the test.

Part 2

We need to take 2 blood samples from your child's IV access. These are usually done 1.5 hours after the radioactive medicine has been given and again 1 hour after that. Your child can leave the department betweeen the 2 blood samples and you will be told what time to return for each.

Once the second sample is done the test will be finished. These blood samples will help the doctor see how well the blood is flowing through your child's kidneys.

Post test

Please give your child extra fluids for the rest of the day to keep them hydrated and help the medicine leave the body quicker.  

The scan results are given by a doctor specialized in Nuclear Medicine and not by the technologist doing the test.  A report is sent to your doctor’s office, usually within 2-3 business days. 

Please call the Nuclear Medicine Department at 416-813-6065 if you have any questions about the procedure or if you need to change the appointment.

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