Fasting blood glucose in healthy people is usually between 3.9 and 6.1 mmol/L. Fasting blood glucose is the blood glucose level measured in the morning after fasting from the previous night and not eating for at least 8 to 10 hours. If the fasting blood glucose level is above the normal range, it may be diabetes, or it may be caused by infection, stress, or other factors that need to be taken seriously. In addition to paying attention to fasting blood glucose, healthy people can also regularly monitor indicators such as 2-hour postprandial blood glucose or glycated hemoglobin to comprehensively assess their blood glucose status. Patients who are found to have abnormal fasting blood glucose should go to the hospital in time and be diagnosed and treated under the guidance of a professional doctor to avoid delaying their condition.