Whether fasting blood glucose 8.0mmol/L is serious depends on whether the patient is diabetic or normal. Diabetic patients fasting blood glucose 8.0mmol / L has been higher than the control target, is a more serious situation; normal people may be physiological hyperglycemia may also be pathological hyperglycemia, it is recommended to consult a doctor in time to clarify. 1. Diabetes mellitus is mainly manifested as chronic hyperglycemia, generally speaking, patients with type 1 and type 2 diabetes mellitus are recommended to control the fasting blood glucose level at about 4.4~7.0mmol/L, the non-fasting blood glucose target is <10.0 mmol/L, and the glycated hemoglobin should be <10.0%, which is a more reasonable range. 7.8mmol/L is a little bit higher than the target, and it is recommended to continue monitoring and adjusting the glucose-lowering program in due course. If 7.8 mmol/L is slightly higher than the target value, continued monitoring is recommended. 2. A normal fasting blood glucose of 8.0 mmol/L means that there is elevated fasting blood glucose, which is more serious. If there are typical symptoms of diabetes mellitus, fasting 8.0mmol / L can be diagnosed as diabetes mellitus, should be under the guidance of a physician reasonable diet and exercise, oral hypoglycemic therapy if necessary, such as stress, hyperthyroidism and other causes of elevated blood glucose, it is recommended that the treatment of primary disease. However, physiological hyperglycemia may also occur in normal people, such as emotional excitement before blood glucose measurement, strenuous exercise, etc. Reactive hyperglycemia may also occur, which is a normal physiological reaction and can be recovered on its own, and is generally not serious. If you feel unwell, please go to the hospital for consultation.