Use of gadolinium diethylene triamine penta-acetic acid, as measured by ELISA, in the determination of glomerular filtration rates in cats

The goal of this study was to evaluate a commercially available assay for gadolinium diethylene triamine penta-acetic acid (Gd-DTPA) for use in estimating glomerular filtration rate (GFR) in cats (Gd-DTPA GFR) with a wide range of GFRs. Eighteen adult cats (11 healthy and seven with chronic kidney disease) were included. Plasma concentrations of Gd-DTPA following intravenous injection were measured with an ELISA kit (FIT-GFR). Results for Gd-DTPA GFR were compared with simultaneously obtained values for plasma clearance of iohexol (iohexol GFR), plasma blood urea nitrogen (BUN) and creatinine concentrations. A negative correlation existed between iohexol GFR and plasma concentrations of BUN and creatinine. A positive correlation existed between Gd-DTPA GFR and iohexol GFR. There was no correlation between Gd-DTPA GFR and plasma concentrations of BUN and creatinine. In this study plasma clearance of Gd-DTPA assayed by FIT-GFR did not appear to provide a sufficiently accurate estimation of GFR in cats when compared with plasma clearance of iohexol, and plasma concentrations of BUN and creatinine.