There are three main types of diabetes: type I diabetes, type II diabetes, and gestational diabetes, and it is not usually possible to determine the type of diabetes based on a fasting blood glucose of 14.8 mmol/l. Commonly, there is a need to identify type I diabetes and type II diabetes, which can be determined by combining age at onset of diabetes and diabetic autoantibodies. Autoantibodies include anti-human insulin antibodies, anti-insulin cell antibodies, glutamic acid decarboxylase antibodies, and anti-tyrosine phosphatase antibodies. Type I diabetes mellitus starts in most adolescent patients, and the symptoms are more obvious; if not diagnosed and treated in time, diabetic ketoacidosis can occur when there is a serious lack of insulin, and type I diabetes mellitus tests for diabetic autoantibodies are positive. Type II diabetes can occur at any age, but most common in adults, often after 40 years of age; most of the onset of insidious, relatively mild symptoms, more than half of no symptoms; many patients due to chronic complications, concomitant disease, or only in the health checkup found. Fasting blood glucose 14.8mmol/l, need to go to the local hospital endocrinology department, clear diabetes type, then targeted treatment.