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Your doctor has requested a GFR study of your kidneys. This booklet will answer some of the questions you may have. 

What is a GFR study? 

A GFR study is used to determine how well your kidneys are working by removing waste and excess fluid from the blood. This procedure involves multiple blood samples taken over a period of 4 hours. 

What is involved? 

This test includes several parts, which will occur at different intervals over the course of about 4 hours. 

Part 1 (20 – 60 min): When you arrive in the Nuclear Medicine department, a technologist will explain the entire procedure to you and then give you the opportunity to ask any questions. The technologist will then set up an intravenous catheter in a vein in one arm. This will be used for taking blood samples.  The technologist will then give you an injection of a radioactive tracer into a different vein. There are no known side effects from this injection. If your physician is also interested in taking pictures of the function of your kidneys, this injection will be given while you are on an imaging table under a special detector called a gamma camera. Following the injection (and scan if required), you will be free to leave the department, returning at three separate one-hour intervals later in the day. The technologist will give you these return times before you leave the department. 

Parts 2, 3 and 4 (10 min): When you return for each of these short visits, the technologist will take a sample of your blood for analysis. Once all the blood samples have been completed, you will be free to go home, with no ill effects from the procedure.  

Do I need to prepare for the scan? 

• Bring your Health card. 
• The results of this study will be improved if you drink at least 0.5 liters of water starting one hour before your appointment. Food will not interfere with this study. If you are taking medications, you may continue as usual. 
• Please leave all valuables at home. 
• Since there may be a few hours waiting time between imaging during this procedure, it may be beneficial to bring some reading material. There is free Wi-Fi available. 
• Please notify our booking office at the time of scheduling your appointment if you have any concerns regarding a language barrier or any other special needs, so that appropriate arrangements can be made ahead to provide you with the best possible care. 

Will it hurt? 

Only the pinprick of the injection needle may hurt a bit. You may have had a blood test in the past. This is much the same. 

Is the radiation dangerous? 

The injection contains a small amount of radioactive tracer which emits gamma rays (these are similar to X-rays). The radiation dose is very low and will disappear by itself after two days. The results of your scan will give your doctor useful information about your condition and will help them plan your treatment. The benefits of having the scan far outweigh any potential risk from the small radiation dose.  

Do I need to do anything after the scan? 

No special precautions are needed after the scan. If you are travelling across any borders in the seven days after your scan, please ask us for further advice. Border crossings and airports have very sensitive radiation detectors which may pick up tiny amounts of radioactivity remaining after your scan. We will give you a letter that you can show to customs officials at border crossings or airports. 

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

Please tell us if you are pregnant or breastfeeding.  

How will I get the results of my scan? 

A specially trained doctor will examine the pictures. This is normally done soon after the end of the scan. A report is then sent to the doctor who asked us to do the scan. Your doctor will normally receive the report within one week. You will also have access to the report on MyChart as soon as it is released. 

If you have questions about the scan results or report, please contact your doctor directly. They are best able to interpret the report for you. 

Will this test cost me money? 

No. This test is paid for by the healthcare system. The test costs several hundred dollars, so please notify the department at 613-761-4831 if you cannot make your appointment. 

What should I do if I cannot make my appointment? 

If you cannot make you appointment, it is important that you notify the department at 613-761-4831 as soon as possible. Failure to make your appointment results in wasting of expensive materials that are ordered especially for your appointment and also reduces availability to other patients. Missed appointments may also result in delays of your treatments. 

Directions and Parking 

Civic Campus  1053 Carling Avenue – 1st Floor Tel.: 613-761-4831, option 8 Hours: Mon. – Fri., 8:00 a.m. – 4:00 p.m. Directions: From within the Civic Campus, take the “C” elevators to the 1st Floor and follow the signs to Nuclear Medicine. Patients may also ask for directions at the patient information desk.	General Campus  501 Smyth Road – Main level Tel.: 613-761-4831, option 8 Hours: Mon. – Fri., 7:00 a.m. – 4:00 p.m. Directions: From the main entrance, follow the signs on the main level (located at the public elevators). Patients may also ask for directions at the patient Information desk.
Park in either parking lot off Carling Avenue (P7) or in the multistory parking garage (P1).	Park in the parking garage which is located beside the main entrance just off Smyth Road.

Parking instructions 

• All parking lots are automated  
• Take the parking ticket with you inside.  
• When you have completed your appointment, you can pay by cash or credit card at one of our pay stations, or you can pay by credit card with express exit at the parking lot exit gates (the grace period after payment to leave facility is 20 minutes). 
• Payment methods: 
  • Pay stations: Cash or credit card (Visa, MasterCard or American Express). 
• Maximum parking fee is $13.00 

Visit The Ottawa Hospital’s website for additional directions and parking instructions and maps.

Last updated on: April 22nd, 2022