High blood glucose may be diabetes, but a single high blood glucose is not necessarily diabetes. Diabetic patients may have increased blood glucose, but the diagnostic criteria for diabetes mellitus require a fasting blood glucose greater than or equal to 7.0 mmol/l, or a random blood glucose greater than or equal to 11.1 mmol/l, or an oral glucose tolerance test with a 2-hour glucose greater than or equal to 11.1 mmol/l, or a glycosylated haemoglobin greater than 6.5%, in conjunction with the symptoms of the triple polycythemia vera. In the presence of trauma, inflammation, surgery and other stressful conditions, the body may experience a transient increase in blood glucose, after removing the cause of the blood glucose can return to normal, this situation is called stress hyperglycemia, in this case, if the blood glucose measurement increases, need to be repeated on a different day to rule out the stress hyperglycemia situation. People with elevated blood glucose are advised to consult an endocrinologist as soon as possible.