Blood glucose of 18 mmol/L is significantly elevated for both non-diabetics and diabetics and may be more serious. High blood glucose in diabetic patients may lead to acute complications such as diabetic ketoacidosis and diabetic hyperosmolar hyperglycemic syndrome, which may be life-threatening and health-threatening in severe cases. Blood glucose is one of the more common tests in the clinic, the normal value of fasting blood glucose is between 3.9-6.1mmol/L, and the normal value of 2-hour postprandial blood glucose is less than 7.8mmol/L. When the value of blood glucose is 18mmol/L, the blood glucose is significantly higher than the normal value no matter whether it’s fasting or 2-hour postprandial blood glucose. When the blood sugar is abnormal, it is recommended to consult a doctor in time, after diagnosis and treatment under the guidance of the doctor, so as not to delay the condition and cause serious consequences.