Evaluation of a mini-column chromatographic procedure for the measurement of hemoglobin A1c

An ion-exchange chromatographic procedure is described which facilitates the determination of beta-chain aminoterminal modified glycated hemoglobin. The procedure includes an erythrocyte lysis reagent which eliminates the labile aldimine component (pre-A1c) and a two-stage elution step which separates HbA, 1a + b from HbA1c. This procedure also includes calibrator material which aids in correcting for temperature fluctuations during the analysis. Within-run CV's for samples with HbA1c levels between 4.0% and 13.7% were 1.4 to 3.2%. The between-run CV for an HbA1c control was 5.5%. A comparison of the present test to an ion-exchange HPLC method yielded the equation: HPLC = 0.96 (present method) -0.2% (n = 101 and r = 0.984). Two separate reference range studies yielded comparable results (n = 220/65, mean = 4.77/4.78%, S.D. = 0.68/0.55). Studies with pooled erythrocytes and various lipemic plasmas did not reveal any assay interferences. Various abnormal hemoglobins were studied for their effect on the assay.