Evaluation of Accuracy, Precision and Agreement of Five Hba1c Measurement Methods with HPLC Reference Method

Abstract

Background and Objective: The current challenge of diabetes mellitus is to prevent its complications. These complications are directly associated with hyperglycemia in diabetics. The HbA1c measurement is essential for long-term glycemic control. Synchronization of HbA1c measurement is important in order to avoid discrepancies between results reported by laboratories. This study aimed to evaluate the accuracy, precision and agreement of five HbA1c measurement methods with HPLC reference method. Methods: HbA1c levels of 55 samples were measured using six methods of microcapillary electrophoresis (Sepia), enzymatic method (Pishtaz Teb), immunoturbidometry (Pars Azmoon), boronate affinity (Nycocard), immunofluorescence (ichroma) and Tosoh G8 HPLC. Results: The five tested methods showed a good agreement with the HPLC method with correlation coefficient of less than 95%. Regression testing of HPLC method and other methods showed slope of 0.99 (P<0.05) for Sebia, 1.02 (P<0.05) for Pishtaz Teb, 0.79 (P<0.05) for Pars Azmoon, 0.82 (P<0.05) for Nycocard and 0.89 (P<0.05) for ichroma. Average inaccuracy for the Sebia, Pishtaz Teb, Pars Azmoon, Nycocard and ichroma in comparison with the HPLC reference method were -0.09, -0.004, -0.75, -0.79 and -0.78, respectively. Conclusion: The Sebia microcapillary method and Pishtaz teb enzymatic method have appropriate accuracy and precision. Therefore, these methods can be used as alternatives to the HPLC method for HbA1c measurement. Other methods such as Pars Azmoon, Nycocard and ichroma have significant shortcomings in terms of accuracy.