Pre-meal glucose includes fasting glucose and other pre-meal glucose, where fasting glucose is generally the glucose level in the state of fasting for more than 8 hours, and if not specifically referred to, it is generally the glucose in the period from early morning after waking up to before breakfast. Occasionally, some doctors will consider the blood sugar before the next meal also belongs to fasting blood sugar. The normal level of fasting blood glucose varies in different people. The normal fasting blood glucose for a person is generally 3.9-6.1 mmol/L. When it is below or above this level, it is considered abnormal. When the blood sugar is below 2.8 mmol/L it is hypoglycemia. More often than not, it is above the upper limit of normal levels. When the blood sugar is higher than 6.1mmol/L and lower than 7.0mmol/L, it is called impaired fasting glucose regulation. At this time, a comprehensive assessment should be made considering both the patient’s symptoms and postprandial blood sugar, and if necessary, a glucose tolerance test should be performed. Some people consider this stage as pre-diabetes. When the fasting blood glucose further rises above 7.0mmol/L, the possibility of diabetes should be highly suspected. While other normal reference levels of pre-meal glucose are drawn from fasting glucose, there is no separate normal level. Therefore, the pre-meal blood glucose is generally based on fasting blood glucose, which is normally at 3.9-6.1mmol/L. When the pre-meal blood glucose is elevated, it may be related to too much food in the last meal, or it can be related to insufficient dose of therapeutic drugs after diabetes is diagnosed, which needs specific analysis and judgment.