Comparison of serum fructosamine and glycated hemoglobin values for assessment of glycemic control in dogs with diabetes mellitus

OBJECTIVE To evaluate the performance of 2 assays for measurement of serum fructosamine (SF) and glycated hemoglobin (HbA1c) values in dogs and to compare the usefulness of the 2 glycated proteins for assessment of glycemic control in dogs with diabetes mellitus (DM). SAMPLE Blood samples from 40 healthy dogs, 13 diabetic dogs, and 23 anemic nor-moglycemic nondiabetic dogs and results of 200 assessments of glycemic control in 46 diabetic dogs. PROCEDURES Colorimetric and immunoturbidimetric methods were used for measurement of SF and HbA1c values, respectively. Linearity and precision were determined. The usefulness of SF and HbA1c values for assessment of glycemic control was evaluated with a clinical scoring method used as the reference standard. Cutoff values obtained from receiver operating characteristic curves were used to identify the percentage of dogs correctly categorized by means of SF and HbA1c values. RESULTS Mean intra-assay and interassay coefficients of variation were 3.8% and 2.5%, respectively, for the SF assay, and 1.2% and 1.8%, respectively, for the HbA1c assay. Excellent linearity (R2 > 0.99) was obtained for both assays. Values for SF and HbA1c were inversely correlated (r = –0.40 and –0.33, respectively) with clinical score and correctly indicated glycemic control in 99 of 200 (50%) and 88 of 200 (44%) assessments, respectively. CONCLUSIONS AND CLINICAL RELEVANCE The SF and HbA1c assays were precise, had good linearity, and appeared to be suitable for routine use in veterinary medicine. However, they performed poorly for classifying glycemic control in diabetic dogs.