Comparison of Three Different Assay Procedures for the Determination of HbA 1 with Special Attention to the Influence of Pre-HbA 1c,Temperature and Haemoglobin Concentration

Three different methods for the measurement of glycated haemoglobin or HbA₁, based on agar gel electrophoresis, ion-exchange and affinity chromatography were compared. All three showed acceptable precision (overall CV being less than 5%) and correlated well with each other (r> 0·945). The ion-exchange and affinity chromatography method proved to be independent of the amount of pre-HbA_1c present. The electrophoresis method was independent of temperature in contrast to the other two methods, which shewed a strong and comparable temperature dependency. All three methods were dependent on the haemoglobin concentration and/or protein content of the haemolysate. Both ion-exchange and electrophoresis showed significant interference by changes in haemoglobin concentrations, whereas the protein concentration significantly biased the affinity chromatography figures. Taking into account their specific merits all three methods are acceptable for routine use.