Measurement with High-Performance Liquid Chromatography (HPLC)

The global prevalence of diabetes mellitus is increasing rapidly. Measurement of glycated hemoglobin, predominantly HbA1c, is fundamental to the management of patients with diabetes. HbA1c is used to monitor long-term glycemic control, adjust therapy, assess the quality of diabetes care and predict the risk for the development of complications. While HbA1c is the standard indicator for long-term glycemic control in diabetes, there are different methods for measurement of HbA1c and all laboratories do not use the reference method of high-performance liquid chromatography (HPLC). This study aimed to compare three different methods of measuring HbA1c with HPLC to find out which method have acceptable concordance and correlation with the reference method. 58 patients with diabetes mellitus were assessed. Blood sample of each patient was checked via Diazyme (enzymatic assay), Nycocard (boronate-affinity binding) and Biosystem (microcalumn chromatography). The values of HbA1c in each method were compared with the Knauer-HPLC results. The mean (SD) of differential values between each method and HPLC in ANOVA test was 1.8 (1.09) for Nycocard-HPLC, 1.5 (1.08) for Biosystem-HPLC, and 1.3 (1.2) for Diazyme-HPLC. Pearson's correlation coefficient was 0.76 between Nycocard and HPLC, 0.75 between Diazyme and HPLC and 0.68 between Biosystem and HPLC. With HPLC linear regression parameters were also determined for each method. Diazyme had a better performance and showed a greater concordance with HPLC among others; although it was not an ideal alternative for HPLC.