Use of the turbidimetric method for determining hemoglobin (A1C) in diabetic and nondiabetic dogs

Canine diabetes mellitus is a multifactorial disease with a worldwide prevalence of 0.005 to 1.5%, affecting dogs between 4 and 14 years of age, males and females. Persistent fasting hyperglycemia and glycosuria confirm the diagnosis, and glycated hemoglobin (A1C) is an efficient biomarker for the risk of complications and monitoring. The scarcity of unvalidated reference values and commercial kits justifies its low application in veterinary medicine. The aim of this study was to identify A1C as a diagnostic biomarker of diabetes mellitus in dogs through immunoturbidimetry assay and to propose an A1C reference range for diabetic and nondiabetic dogs. We randomly selected 86 healthy dogs and 20 diabetic dogs of different ages and breeds, both male and female, neutered and not neutered. Hemogram, urea, creatinine, alanine aminotransferase, alkaline phosphatase, glycemia, and glycated hemoglobin were performed using the turbidimetry assay. The Spearman correlation test between A1C and the biochemical and hematological variables, ROC curve to analyze the diagnostic capacity of glucose, and A1C to predict diabetes in dogs was used. We obtained a median of 3.8% for A1C with a confidence interval of 3.8 to 4.0% for nondiabetic dogs and a cut off of 4.5% for diabetic dogs. Spearman’s correlation showed a direct relationship between A1C and glucose and a statistically significant association with glucose (p < 0.001) and creatinine (p < 0.002). The areas of the ROC curve of A1C and glucose had good indices in their individual use, and their association showed a positive and statistically significant correlation (p = 0.051). The diagnostic ability of A1C to predict diabetes mellitus in dogs was confirmed and A1C reference range established for nondiabetic and diabetic dogs, also showing association with creatinine, given this relevant and unprecedented data in the veterinary literature.