Determination of glycated hemoglobin by affinity chromatography

An affinity chromatography microcolumn assay for glycated hemoglobin was compared with electrophoretic and microcolumn ion exchange methods. The affinity method has an imprecision of less than 4% for non-diabetic and less than 2% for diabetic specimens. The method is neither affected by carbamylated or acetylated hemoglobin nor by high glucose concentrations. Method comparisons showed discordant results due to interferences in electrophoretic and ion exchange methods in 3%-6.5% of all cases. Nonlinear relationships between affinity methods on one hand and electrophoretic as well as ion exchange methods on the other indicate that the affinity method measures not only beta-terminal glycated hemoglobin but all glycated hemoglobins, providing enhanced sensitivity and diagnostic value.