Hemolysis causes a decrease in HbA1c level but not in glycated albumin or 1,5-anhydroglucitol level

HbA1c has been widely used as a glycemic control indicator or as a diagnostic indicator for diabetes mellitus. However, HbA1c is affected by the erythrocyte life span and, therefore, shows falsely low values in hemolytic patients. Erythrocyte creatine (EC) is a sensitive hemolytic marker that reflects the mean erythrocyte age. In the present study, the relationships of HbA1c, glycated albumin (GA), and 1,5-anhydroglucitol (1,5-AG) with different hemolytic markers, including EC, were investigated in non-diabetic individuals. A total of 43 non-diabetic individuals whose complete blood count and reticulocytes were measured via medical examinations were included in this study (28 individuals with hemolysis and 15 individuals without hemolysis). Those with suspected diabetes mellitus based on medical history, low 1,5-AG values, or had comorbid liver and renal diseases were excluded from this study. HbA1c, GA, 1,5-AG, and various hemolytic markers were measured to examine the correlation of the glycemic control indicators with the various hemolytic markers. A significant correlation was observed between GA and 1,5-AG but not between HbA1c and GA or 1,5-AG. Significant correlations were observed between HbA1c values and various hemolytic markers (reticulocytes, haptoglobin, and EC) but not between GA or 1,5-AG values and those hemolytic markers. HbA1c, but not with GA and 1,5-AG, showed significant correlations with the hemolytic markers. These results suggested that HbA1c does not reflect the glycemic control accurately in hemolytic patients, while GA and 1,5-AG values are not affected by mean erythrocyte age and, therefore, accurately reflect the glycemic control.