HbA1c is used to evaluate the blood glucose control situation of diabetes patients for the last 2 – 3 months. The test results are shown in percentage (%) so that the diabetes patients who are familiar with blood glucose units in mg/dL or mmol/L will be easily confused. The American Diabetes Association, the European Association for the Study of Diabetes, and the International Diabetes Federation worked together to develop a global standard to interpret the relationship between HbA1c and average blood glucose (eAG). The calculation formula is: (28.7*HbA1c) – 46.7 = average blood glucose value (eAG). The following table can provide you with the average blood glucose value (eAG) that corresponds to the HbA1c. With this table, you can clearly understand the blood glucose control situation.