Comparison of four chromatographic methods used for measurement of glycated hemoglobin

Abstract

This parameter’s results accuracy has a special importance in the management of diabetic patients since targets for optimal glycemic control are established using HbA1c values. Several error sources can influence the obtained value, some of them can be counteracted (ex. pipetting errors, storage), and others should be taken into consideration at the interpretation of the result (ex. presence of hemoglobin variants). The aim of this study was to compare four chromatographic methods regarding the costs and the influence of certain error sources on the accuracy of the result. Materials and methods: Samples and controls were analyzed using Variant I, Micromat II and In2it (Bio-Rad) systems, and the BIOMIDI reagent kit for HbA1c measurement. Results: Positive correlation could be observed comparing the results obtained using different methods, except the patients presenting elevated HbF. Pipetting errors modify the results up to 5% in case of Variant I, and up to 10% in case of Micromat II in the tested range. One day of improper storage at room temperature causes 3% deviation from the actual value using the Variant I analyzer and 5% in case of Micromat II and In2it equipment. As a conclusion, depending on the number of samples, automated chromatographic analyzers are the most appropriate equipments for the determination of HbA1c.

Keywords

• glycated hemoglobin
• high pressure liquid chromatography
• hemoglobin variants
• method comparison
• error sources