title: Plasma exogenous creatinine clearance test in dogs: comparison with other methods and proposed limited sampling strategy.
abstract: Plasma clearance of creatinine was evaluated for assessment of glomerular filtration rate (GFR) in dogs. In 6 healthy dogs (Experiment 1), we determined 24-hour urine clearance of endogenous creatinine, plasma, and urine clearances of exogenous creatinine administered at 40, 80, and 160 mg/kg in a crossover design (linearity study), plasma iothalamate clearance, and plasma and urine clearances of 14C-inulin. In Experiment 2, plasma creatinine and iothalamate clearances were compared, and a linearity study was performed as for Experiment 1 in 6 dogs with surgically induced renal impairment. Experiment 3 compared plasma creatinine clearance with plasma iothalamate clearance before and 3 weeks after induction of moderate renal impairment in 6 dogs. Plasma creatinine clearances were calculated by both noncompartmental and compartmental analyses. In Experiment 1, plasma inulin clearance was higher (P < .001) than other clearance values. Plasma creatinine clearances at the 3 dose rates did not differ from urine inulin clearance and each other. In Experiment 2, plasma creatinine clearances were about 14% lower than plasma iothalamate clearance (P < .05). In Experiment 3, decreases in GFR assessed by plasma clearances of iothalamate and creatinine were similar. Renal failure decreased the daily endogenous input rate of creatinine by 25%. Limiting sampling strategies for optimizing GFR calculation were proposed, allowing an error lower than 6.5% with 4 blood samples. These results suggest that determination of plasma creatinine clearance by a noncompartmental approach offers a reliable, inexpensive, rapid, and convenient means of estimating GFR in routine practice.
authors.affiliation: Veterinary Medicine, The University of Sydney, NSW, Australia. adjw@vetc.usyd.edu.au
authors.forename: A D J
authors.initials: AD
authors.lastname: Watson
authors.forename: Hervé P
authors.initials: HP
authors.lastname: Lefebvre
authors.forename: Didier
authors.initials: D
authors.lastname: Concordet
authors.forename: Valérie
authors.initials: V
authors.lastname: Laroute
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Ferré
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Braun
authors.forename: Fabrice
authors.initials: F
authors.lastname: Conchou
authors.forename: Pierre-Louis
authors.initials: PL
authors.lastname: Toutain
mesh_terms: D000818:Animals; D019540:Area Under Curve; D003404:Creatinine / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D018592:Cross-Over Studies; D004283:Dog Diseases / Q000503:physiopathology; D004285:Dogs / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005919:Glomerular Filtration Rate / Q000662:veterinary*; D007444:Inulin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D007483:Iothalamic Acid / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008297:Male; D011237:Predictive Value of Tests; D012016:Reference Values; D051437:Renal Insufficiency / Q000503:physiopathology / Q000662:veterinary; D013048:Specimen Handling / Q000662:veterinary
chemical_list: D007483:Iothalamic Acid; D007444:Inulin; D003404:Creatinine