Glucose (blood sugar) is an indicator of diabetes mellitus. It depends on factors such as diet, daily stress, nutrition. If it is high or borderline, it is hyperglycemia, if it is low, it is hypoglycemia. Both situations are related to one’s energy needs. It is manifested by diseases characterized by a complete deficiency, insufficient or, on the contrary, excessive secretion of the insulin hormone, which regulates the use of sugar released from the pancreas. If insulin is not secreted or insufficient, it is called Type I diabetes. If it is secreted but still has high blood sugar, it is called insulin resistance, that is, Type II diabetes. Glucose is evaluated by standard fasting for 12-14 hours. If it is high or very low, the doctor asks for further tests and perhaps follows a clinical path to reveal hidden diabetes.