You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Single-injection inulin clearance has been reported to be a cheap, simple way of measuring Glomerular Filtration Rate (GFR) in dogs. Here is a description of the method.

Assessment of renal function is important in small animal practice. GFR can be measured by conduction the following test :

• Withhold food for 12 hours prior to the test
• Allow free access to water at all times
• If the patient is on IV fluid therapy stop this for 48 hours prior to the test
• Collect a blood sample into a plain sterile container
• Give an intravenous injection of Polyfructosan-S (Sinistrin) - 100mg per kg body weight OR 3000 mg per m² body surface (recommended)
• Collect blood samples at 20, 40, 80 and 120 minutes after the injection into a plain sterile container OR take a single sample after 120 minutes
• After the blood has clotted centrifuge and collect the serum for despatch to diagnostic laboratory

Using this technique the calculated GFR for :

• normal dogs has been reported to be 83.5-144.3 ml min^-1 m^-2   or  2.73-6.56 ml min^-1 kg^-1
• dogs with suspected impaired renal function to be 60.2-96.7 ml min^-1 m^-2  or  2.14-3.7 ml min^-1 kg^-1 
• dogs with polydipsia and polyuria 50-76.2 ml min^-1 m^-2  or 2.14-3.54 ml min^-1 kg^-1
• dogs with azotaemic renal disease 16.3-63 ml min^-1 m^-2 or 0.59-1.98 ml min^-1 kg^-1 

Small dogs have a higher metabolic rate and so clear inulin quicker than larger dogs.

A major advantage of this technique is the ability to detect reduced renal function in dogs with normal blood urea or creatinine concentrations, and so it is a useful screening test for the early detection of disease in high risk patients.

Reference

Haller H. et al. (1998) Research in Veterinary Science 64 : p151-156.

Last updated : October 2016