It is not necessary to drink sugar water to review blood glucose, but only the OGTT test, which is a glucose tolerance test, is required in clinical practice to check what blood glucose can be achieved after a sugar load and to see if the diagnosis of diabetes can be met. At the same time, you can check the insulin release level to determine the specific degree of damage to pancreatic islet function. The purpose of reviewing blood glucose in daily life is mainly to assess whether the blood glucose meets the standard. This assessment requires monitoring the blood glucose in fasting and 2 hours after three meals under the premise of normal diet, exercise and medication. Usually, pure carbohydrates, like icing sugar, white sugar and sugary drinks must not be ingested, except for the occurrence of hypoglycemia which requires sugar water.