Immediate Elimination of Labile HbA_1c With Allosteric Effectors of Hemoglobin

Our aim was to find a simple method of removing labile glycosylated hemoglobin (HbA_1c) from blood samples before it is measured by cation-exchange chromatography. Labile HbA_1c is formed by the binding of glucose to the NH₂-terminal valine of the β-chain of HbA. We sought a more competitive binder for the same site to dissociate labile HbA_1c to glucose and HbA. Inorganic phosphates were found to have a strong allosteric effect and a great ability to eliminate labile HbA_1c. We developed our method with 4 mM tetrapolyphosphate in the hemolyzing solution to eliminate labile HbA_1c during the automatic processing (at pH 6 and heated for 2 min at 45°C) of blood samples for HbA_lc estimation. This may be useful when estimating HbA_1c by the manual method.