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GFR Measurement

GFR Measurement

A Glomerular Filtration Rate (GFR) measurement is carried out to measure how well your kidneys work.

What is involved?

A small amount of radioactive tracer is injected into a vein, usually in your arm. The injection is no more painful than a blood test.

After a delay of three to four hours we will take a blood sample from another vein, again in your arm, and after a further two hours we will take a second blood sample. The whole test will therefore take between five to six hours, however you may leave the department between each part of the procedure provided you attend for the blood samples at the times given to you by the technician or radiographer.

After the second blood sample you will be free to go.

Do I need to do anything before and after the test?

·           On the morning of the test have a light breakfast as    well as a light lunch e.g. a sandwich. It is recommended to avoid high protein meals on the day of the study until the last blood sample has been taken.

·           Do not consume any caffeine from 10pm the previous day as this can affect the result. Caffeine can be found in tea, coffee, hot chocolate, green tea, coca cola, energy drinks and some cold/flu medicines.

·           After the last blood sample has been taken you can eat and drink normally.

Is the radiation dangerous?

The substances we inject are non-toxic and will not make you feel sick or drowsy. The amount of radiation you will receive is small and your doctors consider that the benefit of you having this test significantly outweigh the small risk from this radiation.

However, for radiation safety reasons children should not be brought to the Nuclear Medicine Department unless they are the patient.

What about children, pregnancy or breastfeeding?

Please tell us as soon as possible before the injection if you are pregnant or think that you may be pregnant. All female patients between the ages of 10 - 55 years will be asked to complete a form requesting this information on arrival.

There is no need to interrupt breastfeeding for this test.

Can I bring a friend or relative with me?

A friend or relative can attend with you but they will not be able to accompany you for the injection or when we take the blood samples. Other patients attending the Nuclear Medicine Department may have been injected with larger amounts of radioactivity so we ask that children should not accompany you to the Department.

Can I return to work after my test?


What about my result?

As the blood samples will be analysed at a later time we are unable to tell you the result of the test. The results will be sent to the doctor who requested the test.

Can I get help with transport costs?

If you are receiving certain benefits and meet certain conditions, you will be able to claim back the cost of transport for you and your child for this test. You should take your travel receipts, appointment letter and proof that you are receiving one of the qualifying benefits to the cash office. The cash office is open from 9am-1pm and 2pm-4pm and is on level 1 (our reception staff can direct you). You can get more information from this website.

Where can I get more information?

If you have any further questions after reading this information, please contact:

The Nuclear Medicine Department

Telephone number: 01202 442499

Email address:

Authors:  Nuclear Medicine Team      Version number:  7

Date: June 2019         Review date: June 2022

Head of Nuclear Medicine: Dr Kat Dixon

Principal Medical Physicist: Mrs Emma O’Shaughnessy

Superintendent Radiographer: Mrs Ali Fallows

Responsible Clinician: Dr M Kay, Consultant Radiologist

Hospital services A-Z

Poole Hospital NHS Foundation Trust, Longfleet Road, Poole, Dorset BH15 2JB. Tel: 01202 665511

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