Assessment of glomerular filtration rate in dogs with renal insufficiency: analysis of the 51Cr-EDTA clearance and its relation to the plasma concentrations of urea and creatinine.

The glomerular filtration rate (GFR) was determined with the single injection 51Cr-EDTA clearance in 48 dogs with renal disease and the results were compared with the plasma Creatinine (PC) and plasma urea (PU) levels. The superiority of PC values over PU values for the assessment of the GFR is represented by the power functions PC = 78.2 CR(-0.67) mmol per litre and PU = 10.3 Cr(-0.52) mmol per litre, in which Cr is the relative glomerular filtration rate. The higher correlation between PC and Cr (r = 0.834) than between PU and Cr (r = 0.693) also demonstrates this superiority. An extended two compartment analysis of the 51Cr-EDTA plasma disappearance curve is not essential for diagnostic purposes.