There are diagnostic criteria for hyperglycemia, i.e. if fasting glucose exceeds 6.1 mmol/L it is considered elevated, and if 2 hours postprandial glucose exceeds 7.8 mmol/L it is also considered elevated. If fasting glucose is between 6.1-7.0mmol/L, it is defined as impaired fasting glucose, and 2 hours after meal, its glucose is between 7.8-11.1mmol/L, it is defined as abnormal glucose tolerance, also called IGT. If fasting glucose exceeds 7.0mmol/L, or 2 hours after meal glucose exceeds 11.1mmol/L, it can be retested on another day, and if it still exceeds the above standard, it can be diagnosed as diabetes. If the blood glucose still exceeds the above standard, the diagnosis of diabetes can be made. In short, if fasting blood sugar exceeds 6.1mmol/L or 2 hours after meal exceeds 7.8mmol/L, it can be considered as elevated blood sugar. However, the causes of elevated blood glucose are different, and therefore the treatment is different.