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

Abstract

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.

Relationship between Serum Symmetric Dimethylarginine Concentration and Glomerular Filtration Rate in Cats

“…Because of the infrequent use of direct GFR measurement in veterinary practice and the limitations of available markers for renal function, alternate methods that approximate GFR have utility in the diagnosis of chronic kidney disease (CKD) in cats. Measurements of plasma creatinine concentrations are commonly used to assist veterinarians in the diagnosis of CKD in cats, and plasma creatinine concentrations increase when GFR reduces . However, plasma creatinine concentration is impacted by a number of extrarenal factors such as muscle mass that can confound accurate diagnosis, and significant kidney function has already been lost by the time creatinine concentrations are outside of the reference range for normal cats .…”

“…Measurements of plasma creatinine concentrations are commonly used to assist veterinarians in the diagnosis of CKD in cats, and plasma creatinine concentrations increase when GFR reduces. 1 However, plasma creatinine concentration is impacted by a number of extrarenal factors such as muscle mass that can confound accurate diagnosis, 2 and significant kidney function has already been lost by the time creatinine concentrations are outside of the reference range for normal cats. 3 Urine specific gravity can be helpful in assessing kidney function, but urine samples are often not collected in routine clinical practice despite their diagnostic utility.…”

Effective removal of gadolinium with hemodialysis in a dog with severe acute on chronic kidney injury

“…As mentioned previously, gadolinium has been used to measure GFR in both dogs and cats. 17,18 In addition, clearance of gadolinium would have been portrayed more accurately by obtaining 2 additional serum samples, 1 between the initial injection and before the first hemodialysis treatment, and the other 12 hours after the second hemodialysis treatment, accounting for the distribution of gadolinium from the intravascular space to the extravascular space, and vice versa, after hemodialysis. It is likely the shorter half-life between T0 and T1 (2.7 h) compared with T2 and T3 (12.4 h) can be explained by extravascular distribution of the gadolinium, which has been elucidated in early pharmacokinetic studies performed in healthy human subjects.…”

“…16 Gadolinium has been studied in dogs and cats to determine glomerular filtration rate (GFR), but the measured half-life has not been determined in these species. [17][18][19] In people, the half-life of gadolinium increases exponentially with reductions in creatinine clearance, translating to an elimination half-life of 5.6 hours in people with chronic kidney disease (CKD) stage 2, 9.2 hours for CKD stage 4, and 34.3 hours for people with CKD stage 5 not receiving hemodialysis. 20 Between 12% and 20% of the NSF cases have occurred in patients with acute kidney injury (AKI), often associated with acuteon-chronic disease and predominantly associated with group 1 GBC agents.…”