The normal value of fasting blood glucose is 3.9-6.1 mmo/L. The presence of a fasting blood glucose of 15.1 mmo/L implies that if blood glucose is not controlled in a timely manner, blood glucose may rise further, leading to acute complications. In the short term, if hyperglycemia is not effectively controlled, it can induce acute complications, including diabetic ketoacidosis, hyperosmolar hyperglycemic syndrome, and in severe cases, coma, shock, and cerebral edema, which may be life-threatening. In the long term, hyperglycemia can involve all organs and tissues of the body, with complications such as diabetic nephropathy, diabetic retinopathy, diabetic peripheral neuropathy, etc., which seriously affects the quality of life. Patients with fasting blood glucose of 15.1 mmol/L are advised to seek prompt medical attention and treatment under doctor’s supervision.