Glomerular filtration rate is the most sensitive and accurate indicator of renal function.
The GFR is the rate at which the kidneys remove a filtration marker from a given amount of plasma per unit of time. Several methods are used to estimate GFR in dogs, with urinary clearance of inulin as the criterion-referenced standard.
Urinary clearance of endogenous and exogenous creatinine also yields accurate assessments of GFR in dogs. However, these procedures are time-consuming and require meticulous urine collection with urinary catheters or metabolic cages. Protocols that involve the use of urinary catheterization have the risk of causing an iatrogenic urinary tract infection. For these reasons, other methods have been explored, including plasma clearance, nuclear scintigraphy and functional computed tomography.
GFR has practical applications since it allows assessment of electrolyte excretion. As GFR falls, the unit of electrolyte excretion per unit glomerular filtration rate normally increases.
- Dworkin LD & Brenner BM (2000) Biophysical basis of glomerular filtration. In: Seldin DW, Giebisch G, eds. The kidney: physiology and pathophysiology. New York: Lippincott, Williams & Wilkins. pp:763
- Finco DR et al (1993) Endogenous creatinine clearance measurement of glomerular filtration rate in dogs. Am J Vet Res 54:1575–1578
- Finco DR et al (2001) Relationship between plasma iohexol clearance and urinary exogenous creatinine clearance in dogs. J Vet Intern Med 15:368–373
- Krawiec DR et al (1986) Evaluation of 99mTc-diethylenetriaminepentaacetic acid nuclear imaging for quantitative determination of the glomerular filtration rate in dogs. Am J Vet Res 47:2175–2179
- O’Dell-Anderson KJ et al (2006) Determination of glomerular filtration rate in dogs using contrast-enhanced computed tomography. Vet Radiol Ultrasound 47:127–135