HbA1c concentrations in the blood can be expressed in percentage (= NGSP unit) or mmol/mol (= IFCC unit). According to the consensus statement on the worldwide standardization of HbA1c measurement, HbA1c may be optimally indicated as mmol/mol. Another measure of long-term glycemic control is the estimated average glucose (eAG). Below you may find a calculator and a conversion table, including HbA1c according to NGSP and IFCC as well as eAG. For calculation of eAG in relation to HbA1c (%) we used the following formula resulting from linear regression analysis of continuous glucose monitoring observed over a period of 2 yr: eAG (mg/dl) = (28.7 x HbA1c) - 46.7, which was published by the ADAG Study Group in 2008. The calculatation rule applied for conversion of HbA1c (%) to HbA1c (mmol/mol) et vice versa is:
