Quantification of Hemoglobin A1c by Reference Measurement Method in National Medical Reference Laboratory

Cho Chan Ik, Lim Ye Sul, Ryoo Jee Hye, Kim Il- yeol
Divsion of Chronic Disease Prevention, KCDC

Hemoglobin A (HbA), which accounts for 97% of the hemoglobin found in adults, is divided into hemoglobin A1a (HbA1a), hemoglobin A1b (HbA1b) and hemoglobin A1c (HbA1c). These hemoglobin are called glycated hemoglobin. HbA1c is formed by the condensation of N-terminal valine radicals and glucose in each beta chain of HbA and is characteristic of diabetic patients. The HbA1c concentration has a good correlation with fasting blood glucose, daily mean blood glucose levels, or urinary glucose. In addition, the probability of HbA1c formation is in direct proportion to blood glucose concentration, and it is used as an additional criterion for evaluating blood glucose control because it is not affected by exercise or recent food intake. Liquid chromatography/mass spectrometry is applied to quantitatively analyze whole blood HbA1c. The assay colonic substance is the n-terminal hexapeptides of the hemoglobin beta chain, and the non-glycosylated hexapeptide and the glycated hexapeptide can be measured by a mass spectrometer. First, the washed red blood cells are hemolyzed with water and enzymes are added to decompose them into N-terminal hexapeptides. Liquid chromatography/mass spectrometry is applied to obtain the ratio of glycated hexapeptide to non-glycosylated hexapeptides.

Keywords: Diabetic, Hemoglobin A1c, Liquid chromatography/mass spectrometry