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Kidney Function

Information about your visit for a kidney function test

Your doctor has asked us to perform a kidney function (or EDTA) test.  This is a test in which a small amount of radioactivity is used to tell the doctor how well your kidneys are working. 

What is involved?

The radioactivity is a small quantity of liquid injected into a vein in your arm.  You will then have a small blood sample taken at two, three and four hours after the injection.   

Do I have to stay in the hospital?

Between the injection and the blood samples you are free to leave the department and the hospital if you wish.

Will I have to undress?

You will not need to undress although it is easier to give you the injection and take the blood samples if you wear a top with loose fitting sleeves. 

Do I need to prepare for the test?

No, you can eat and drink as normal. 

Do I need to stop taking my other tablets and medication?

There is usually no need to stop taking your tablets or other medication.  If there is, we will tell you in your appointment letter. 

Will it hurt?

Only the needle ‘pinprick’ might hurt a little.  You should not feel any after effects from the test.  It will not make you sleepy and will not stop you from driving a car.

Is the radioactivity dangerous? 

No.  The amount of radiation you receive is very small (less than you would get from an X-ray examination). 

Do I need to do anything after the test?

You can eat, drink and go where you wish. 

What happens to the results of the test?

The information we get from the blood samples is sent to the doctor who sent you to the Nuclear Medicine department.

Is there anything I should tell the staff before the test?

Yes.  Please tell us before you have your injection if you:

•    are taking any diuretic (‘water’) tablets
•    are, or think you may be, pregnant  
•    are breast feeding

We hope you have found this leaflet helpful.  If you have any questions or want further information, please phone the Department of Nuclear Medicine on 029 2031 6237.

Velindre Cancer Centre 
Velindre Road, Whitchurch, Cardiff, CF14 2TL

This leaflet was written by health professionals. The information contained in this leaflet is evidence based. It is reviewed and updated every 2 years.