Objective: To evaluate 5 commercially available ELISAs for determination of leptin concentrations in serum samples from dogs.
Sample population: Serum samples from overweight-obese and thin-ideal weight clientowned dogs.
Procedures: Serum samples with high and low leptin concentrations (n = 7 samples each) were used for validation of the assays. Intra- and interassay precision, linearity under dilution, spiking recovery, and limit of quantification were determined. In addition, leptin concentrations in thin-ideal weight (n = 8) and overweight-obese (37) dogs were quantified.
Results: Use of 2 of the 5 ELISAs (A and B) revealed reactivity with canine leptin. Intra-and interassay coefficients of variation were < 6.1% and 76%, respectively, for assay A and 14.0% and 13.7%, respectively, for assay B. In assays A and B, dilutions of canine serum pools were used to determine linear regression equations. Recoveries were 77% to 101% for assay A and 67% to 125% for assay B. Significant differences in leptin concentrations between thin-ideal weight and overweight-obese dogs were detected only when analyzed with assay A.
Conclusions and clinical relevance: Among 5 leptin ELISAs evaluated, a canine-specific leptin ELISA had adequate precision, linearity, and ability to discriminate between high and low leptin concentrations corresponding to overweight-obese and thin-ideal weight dogs, respectively.