Radiology - Kidney Function (GFR) Test

Nuclear Medicine Department

Please read this leaflet carefully in conjunction with your appointment letter.

If you require further any information, please contact the Nuclear Medicine Department on 0161 206 4861.

Why do I need this test?

Your doctor would like you to come here for a test called a GFR, this stands for Glomerular Filtration Rate (GFR), which is to measure how well your kidneys are working. There are other alternative tests, but they are not as accurate. You can opt to refuse this test, but we strongly recommend that you should discuss this with your doctor.

Preparation for your scan

• Please confirm your appointment by leaving a message on our 24 hour answer phone 0161 206 4861
• On the evening before the test, you should eat and drink as normal. Have nothing more to eat from midnight until after the test has started the next day
• You can only drink water or fruit juice/cordials as normal after 10 pm on the day before the test. If you are unsure about this do not hesitate to contact the department
• You must not smoke from midnight before the test until after the test is completed
• If you are on Continuous Ambulatory Peritoneal Dialysis (CAPD), you will need to drain the fluid off that morning and leave the tube capped-off. The Renal Unit may do this for you if necessary. Please ensure that you do this before arriving for the test
• If you are taking any medication, you should continue as normal and bring a list of your current medication with you

How is the test performed?

This test will take 4 to 5 hours to complete.

When you arrive in the department, we will first make sure you have followed the preparation instructions correctly and that we can safely carry on with the test. You will then have a blood sample taken and receive an injection of a radioactive substance into a vein, usually in your arm. After this, both arms will be monitored with an instrument capable of detecting radioactivity.

You will have a further two blood samples taken from a different vein, at 2 hours and 4 hours after the radioactive injection and you will be asked to return to the department at set times for this.

During the waiting times between blood samples, you may eat, but only one of the items listed and drink but only from this restricted list below:

Drinks: water, fruit juices and cordials

Food: 2 slices of white toast with jam (no butter) or 2 rich tea or digestive biscuits or 1 piece of fresh fruit (apples, oranges, grapes, watermelon/melon, berries, no bananas).

There are no side effects from the injection; it does not make you sleepy or prevent you from driving a car.

Risks and Limitations

If you think you may be pregnant or if you are breastfeeding, you must contact us before the test date.

You might get a bruise around where we give the injection, not because of the nature of what is being injected, but because the injection site is a vein. The blood sampling sites may also bruise.

You will receive a small radiation dose of about 0.05 mSv, which is less than that for a chest X-ray. To put this in perspective, the average radiation dose received from natural background radiation is just under 3 mSv in one year in the UK.

After the test

After the test, you may go home or to work. You can eat as normal, and you should also drink plenty of fluids for the rest of the day. This will help to remove the radioactivity out of your body, which should completely disappear within 24 hours.

What happens to the results?

A report is sent to the hospital consultant who asked us to perform the test. Allow at least 2 weeks for it to reach your consultant.

Departmental staff are not allowed to give patients the result of any tests directly.

Can I bring a friend or relative?

Only essential carers may remain with you. You must let us know before your test date if you require a carer present.

Please, do not bring children or pregnant adults with you as there may be other patients in the department who might expose them to a small but unnecessary amount of radiation.

What if I cannot attend for my appointment?

If you have any questions about your examination or are unable to make the appointment, please telephone the help line on 0161 206 4861. This is a 24 hour answer phone, but is usually manned Monday to Friday 8.30am to 4pm.

If you prefer you can contact us via email at Radio.isotopes@nca.nhs.uk

Please include your name, address, date of birth and hospital number (if known) on all correspondence.

Please help us to cut our waiting lists. If you need to cancel or change your appointment, call us as soon as you can so that we can give it to somebody else.

I need an ambulance, how do I arrange this?

If you need an ambulance contact:
0161 206 7014 – Salford residents
0800 032 3240 – other areas

Please inform the Nuclear Medicine department if you are arriving by ambulance.

Interpreters

If you need a translator for your examination please contact the Nuclear Medicine department.

Other sources of information

For further information regarding nuclear medicine examinations, visit the British Nuclear Medicine website:
http://www.bnms.org.uk/page/PatientsCarers

If you still have concerns or require further information about this test please contact us at:
Nuclear Medicine Department
Salford Royal Hospital
Stott Lane
Salford
M6 8HD
Telephone: 0161 206 4861