Practical Matters: Practical ways to measure GFR in your patients - Veterinary Medicine
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Practical Matters: Practical ways to measure GFR in your patients



Radiolabeled marker clearance (i.e. renal scintigraphy) can measure the GFR of each kidney individually, which is important if nephrectomy is being considered. This test requires referral to a facility with the necessary equipment and quarantine facilities (i.e. most veterinary schools and some larger specialty practices with a veterinary radiologist on staff). The radioisotope technetium 99m diethylenetriamine pentaacetic acid (Tc-99m-DTPA) is administered intravenously, and radioisotope uptake in the kidney is quantified with a gamma camera over three minutes.6 Patients are quarantined for 24 hours afterward to allow the radioactive marker to be cleared.

Case example: Renal scintigraphy in a senior cat with a renal mass

Lobelia, a 13-year-old spayed female domestic shorthaired cat, was presented for evaluation of polycythemia (PCV 61%) and was found to have a right renal mass. She was not azotemic. Renal scintigraphy was performed. The global GFR of 2.3 ml/min/kg was within the reference range, and function was almost equally split between the two kidneys. The GFR of the left kidney was 1.3 ml/kg/min, which was deemed insufficient to maintain normal homeostasis. Chronic kidney failure seemed a likely outcome if the right kidney was removed. So a subcutaneous vascular access port was placed to facilitate phlebotomy every one to two months. Lobelia lived for another three years before she succumbed to an abrupt cerebrovascular event.

Cathy E. Langston, DVM, DACVIM
Animal Medical Center
510 East 62nd St.
New York, NY


1. Heiene R, Eliassen KA, Risoen U, et al. Glomerular filtration rate in dogs as estimated via plasma clearance of inulin and iohexol and use of limited-sample methods. Am J Vet Res 2010;71(9):1100-1107.

2. van Hoek IM, Lefebvre HP, Paepe D, et al. Comparison of plasma clearance of exogenous creatinine, exo-iohexol, and endo-iohexol over a range of glomerular filtration rates expected in cats. J Feline Med Surg 2009;11(12):1028-1030.

3. Pollard RE, Pasco PJ. Severe reaction to intravenous administration of an ionic iodinated contrast agent in two anesthetized dogs. J Am Vet Med Assoc 2008;233(2):274-278.

4. Lefebvre HP, Watson ADJ. Royal Canin Creatinine Clearance Calculator CD in Early Diagnosis of Chronic Renal Failure. Waltham Focus Special Edition, October 2003.

5. Watson AD, Lefebvre HP, Concordet D, et al. Plasma exogenous creatinine clearance test in dogs: comparison with other methods and proposed limited sampling strategy. J Vet Intern Med 2002;16(1):22-33.

6. Kerl ME, Cook CR. Glomerular filtration rate and renal scintigraphy. Clin Tech Small Anim Pract 2005;20(1):31-38.


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