Comparison of column chromatographic, colorimetric and electrophoretic methods for determination of glycosylated hemoglobin (HbA1)

A comparison of two column chromatographic (BioRad & Helena), an electrophoretic (Corning) and a colorimetric method for the determination of glycosylated hemoglobin (HbA1) was performed. Blood samples were obtained from a diverse diabetic population and normal persons. Inter-and intra-run precision studies with normal and above normal HbA1 samples indicated that there was no statistically significant difference (p greater than 0.05) in precision among the methods. The electrophoretic and BioRad column chromatographic methods showed best correlation (r = 0.96 p less than 0.001 y = 0.465 + 1.036 x), while the colorimetric method gave HbA1 levels consistently higher than those obtained by electrophoresis (r = 0.852 p less than 0.001 y = 4.99 + 0.867 x). The effects of preincubation to remove labile glycosylated hemoglobin with saline or semicarbazide - aniline preincubation were also studied. There was no statistically significant difference (p greater than 0.05) in the HbA1 levels from erythrocytes after saline preincubation as compared to nontreated samples. Further investigation concerning the value of preincubation to remove the labile HbA1 fraction is warranted.