Islet function should be judged according to the patient’s disease type and whether the disease development is controlled by medication in a timely manner, and is not entirely determined by blood glucose level, therefore, islet function cannot be judged by blood glucose value. 1. Type 1 diabetic patients: mainly due to autoimmune dysfunction leading to impaired islet function, when they are infected by antigens, it can lead to serious destruction of β-cells, which can lead to islet function with In severe cases, loss of islet function can occur. 2. Type 2 diabetic patients: Usually, people with high blood sugar can make use of the compensatory increase of beta cells, which in turn increases insulin secretion to fight against excessive blood sugar, called insulin resistance. However, in the long run, pancreatic β-cells will gradually apoptosis, leading to absolute lack of insulin secretion. Therefore, although it is not possible to judge insulin function based on blood glucose values, a prolonged hyperglycemic state will eventually lead to insulin deficiency. To assess insulin function, it is recommended to go to the endocrinology department for an insulin release test, which measures insulin or C-peptide to assess islet function. Depending on the insulin function, a decision will be made whether to treat with medication or to replace the treatment with insulin. Therefore, when diagnosed with diabetes, it is important to apply medication to strictly control blood glucose changes under the guidance of a doctor to try to avoid the deterioration of the disease leading to serious impairment of insulin function. You should also monitor blood sugar changes regularly yourself so that you can adjust your treatment in time. Pay attention to adjust the diet, eat more fresh vegetables and fruits, quit alcohol and reduce the intake of carbohydrates. You need to quit smoking in your daily life, exercise appropriately to control your weight, and maintain a good state of mind.