GFR Renal Function Test

What is a GFR Renal Function Test?

A GFR (Glomerular Filtration Rate) test is used to determine how well your kidneys are working. This test will help the doctor understand the filtration rate of your kidneys and give the appropriate treatment or plan treatments for other conditions.


You must be well hydrated prior to the examination.

Please contact us if you have had a CT or MRI scan with contrast in the last 7days.


If you are pregnant or breastfeeding it is essential that you let us know before your appointment date. If you are a female of child bearing age (12-55 years old), you will be asked about your pregnancy and breastfeeding status. If you are unable to confirm you are not pregnant a pregnancy test may be performed.


All patients are entitled to have a chaperone present for any consultation, examination or procedure where they feel one is required. This chaperone may be a family member or friend. On occasions you may prefer a formal chaperone to be present (ie. trained member of staff).

The examination

Upon your arrival a radiographer will explain the procedure to you and will ask you a few questions about your health records. You will then have a small amount of radioactive tracer injected into a vein in your arm. The injected tracer is carried through the bloodstream and to your kidneys to test how well they eliminate the radioactive tracer.

You will then be sent away and asked to return 2, 3 and 4 HOURS after injection for blood samples. This time gap is to allow your kidneys to filtrate the radioactive substance out of your blood and we monitor it over time. The samples are taken from a different vein to that of the injection

How long will it take?

The examination is carried out over 4 hours but each occasion will take approximately 10 minutes. You are free to leave the department/hospital in the gap between the injection and any blood samples.

Who will be present?

Your scan will be performed by a Nuclear Medicine trained member of staff which stays with you in the room while scanning. In addition we might have students in our department, and they will observe the procedure if you give your permission.

Is radioactivity dangerous?

The amount of radiation involved is similar to that from an x-ray examination. The radioactivity naturally disperses from the body and is largely gone in 24 hours. The very low risk involved is balanced against the benefit of the information the examination provides for your doctors.

After the examination

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.