I-125 Glofil (GFR) Test

What is an I-125 Glofil (GFR) test?

An I-125 Glofil (GFR) test measures the Glomerular Filtration Rate of the kidneys. More simply, it measures kidney function.

We do the test by giving your child an intravenous radiopharmaceutical. This "tracer" is medicine combined with a small amount of radioactive material. We will also take blood samples through an IV catheter. There are no images or pictures taken during this study.

Radiopharmaceuticals are carefully tested. The risk of side effects is extremely small. Most radiopharmaceuticals used in nuclear medicine studies give less radiation exposure than a day at the beach.

What should you do prior to your child's exam?

Your child should not have iodinated contrast media 24 hours prior to the exam.

All children must have SSKI drops before this procedure. The drops protect your child's thyroid from the radioactive portion of the medicine we inject during the study. We will give your child the drops on the day of the exam.

Note: Parents will be allowed to accompany their child into the exam room. It may be helpful to make other arrangements for siblings.

What should you expect during the exam?

A technologist or nurse will place an IV in your child’s arm, hand or foot. Your child may feel a small pinch.

After we draw a blood sample through the IV catheter, we’ll inject your child with the radiopharmaceutical (I-125). We’ll take more blood samples five, 10 and 15 minutes after the injection. You and your child may then leave the Nuclear Medicine department. We’ll give you scheduled times to return.

Typically your child will need to return at two, two and a half, and three hours after the injection for additional blood draws. These times may change according to your child's age, weight or other factors. Again, all blood samples will be taken through the IV catheter.

If you’d like, our child life specialists will help you prepare and support your child during the procedure. We can also arrange to have a child life specialist at your child's appointment to explain the procedure in developmentally appropriate ways and to help your child better cope with the stress of the hospital experience.