A single sample method for evaluating 51chromium-ethylene diaminic tetraacetic acid clearance in normal and hyperthyroid cats.
BACKGROUND
Chronic kidney failure is frequently seen in middle-aged and elderly cats. 51Chromium-ethylene diaminic tetraacetic acid (51Cr-EDTA) clearance and single blood sample (SBS) method are used in several species to estimate the glomerular filtration rate (GFR).


OBJECTIVE
The hypothesis of this study was that 51Cr-EDTA clearance could be determined using an SBS method in normal and hyperthyroid cats.


METHODS
Forty-six cats were included in this study, with an average age of 9.5 years. Of these cats, 27 had hyperthyroidism; 19 were healthy.


METHODS
After IV injection of 51Cr-EDTA (average dose: 4.25 MBq), 7 blood samples were obtained between 5 and 240 minutes. Reference clearance was calculated in mL/min and mL/min/kg body weight, using a 2-compartment model. Optimal time for clearance measurement with SBS was then determined by systematically comparing each individual plasma concentration to the reference multisample clearance.


RESULTS
The average reference plasma clearance of 51Cr-EDTA for all cats was 14.9 mL/min (3.7 mL/min/kg). The clearance in hyperthyroid cats averaged 16.4 mL/min (4.3 mL/min/kg) and in normal cats averaged 10.3 mL/min (2.4 mL/min/kg). The optimal time for the SBS was 48 minutes after injection of tracer 51Cr-EDTA (R2= 0.9414), giving the following converting equation: clearance = (0.0066 x DV48 minutes) - 0.9277 (in mL/min).


CONCLUSIONS
In this study, the single sample 51Cr-EDTA clearance method was used to estimate the global GFR in cats. The method identified differences in clearance between normal and hyperthyroid cats. The optimal time for an SBS was 48 minutes.
Vandermeulen
E
E
Department of Medical Imaging of Domestic Animals, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium. E.Vandermeulen@Ugent.be
van Hoek
I
I
De Sadeleer
C
C
Piepsz
A
A
Ham
H R
HR
Bosmans
T
T
Dobbeleir
A
A
Daminet
S
S
Peremans
K
K
D000465:Algorithms; D000818:Animals; D016022:Case-Control Studies; D002371:Cat Diseases / Q000378:metabolism*; D002415:Cats; D002860:Chromium Radioisotopes; D004492:Edetic Acid / Q000493:pharmacokinetics*; D005260:Female; D005919:Glomerular Filtration Rate / Q000662:veterinary; D006980:Hyperthyroidism / Q000378:metabolism / Q000662:veterinary*; D008297:Male; D012044:Regression Analysis
D002860:Chromium Radioisotopes; D004492:Edetic Acid