Simplified procedure for the estimation of glomerular filtration rate following intravenous administration of iodixanol in cats

Objective-To compare the use of a single-sample method involving IV administration of iodixanol with a multisample method involving inulin for the estimation of glomerular filtration rate (GFR) in cats. Animals-24 cats, including 15 healthy cats and 9 cats with naturally occurring renal diseases. Procedures-Each cat was coadministered iodixanol (a nonionic contrast medium; dose providing 40 mg of I/kg) and inulin (50 mg/kg), IV, and blood samples were collected 60, 90, and 120 minutes later. Serum iodixanol and inulin concentrations were determined by means of high-performance liquid chromatography and colorimetry, respectively. Serum urea nitrogen and creatinine concentrations were also measured. Results-Analysis of the data from healthy cats and cats with naturally occurring renal diseases revealed an excellent correlation between GFR values estimated by the multisample and single-sample methods with iodixanol. Likewise, GFR values estimated from the single-sample method with iodixanol were closely correlated with those calculated from the multisample method with inulin. Conclusions and Clinical Relevance-For estimation of GFR in cats, use of a single-sample method with iodixanol, instead of a multisample procedure, may be an expedient tool in both clinical and research settings because of its benefits to patient well-being as a result of reduced stress associated with blood sample collection.