Diabetes is a chronic systemic metabolic disease characterized by high blood sugar, which can involve many organs of the human body, especially the eyes, kidneys, nerves, heart and blood vessels causing long-term damage, seriously affecting human health. When diagnosing diabetes, you need to recognize the following three misconceptions about diabetes diagnosis: First, if there is sugar in the urine, it must be diabetes – wrong For a long time, many people believe that diabetes patients must have sugar in the urine, otherwise it is not diabetes, in fact, this understanding is not comprehensive. If there is sugar in the urine, it is wrong to think that there must be diabetes because, in normal people, when the blood flows through the kidneys, the glucose in it is filtered through the glomerulus to the renal tubules, and the majority of the glucose in the renal tubules is reabsorbed into the blood, so there is no sugar in the urine, and thus the urine is negative for sugar. Only when the blood sugar exceeds a certain concentration, the glucose in the glomerular filtrate cannot be fully reabsorbed by the renal tubules, and the remaining part is excreted in the urine to form urine sugar, which is the reason why urine sugar is usually positive when you have diabetes. If there is a problem with the renal tubules, they cannot absorb all the glucose considered by the glomerulus and diabetes occurs, it is called nephrogenic diabetes, not diabetes. Second, no sugar in the urine is not diabetes – wrong Diabetes, diabetes, no sugar in the urine, it is naturally not diabetes. Is the presence of sugar in the urine one of the way criteria for diagnosing diabetes? Does diabetes necessarily have the phenomenon of urine sugar? This is actually a misconception. When insulin is not secreted enough, blood sugar will rise, but as long as it does not exceed the renal sugar threshold, urine sugar will not appear, which is clinically called hidden diabetes. Some diabetic patients may not have sugar in their urine, so it should not be taken as a diagnostic criterion. We advocate that people with risk factors for diabetes should have an annual “glucose tolerance test” in order to confirm the diagnosis or exclude hidden diabetes in a timely manner. Some patients have normal fasting blood glucose, but their blood glucose remains high 2 hours after meal, which is also a symptom of diabetes. The incidence of diabetes in China is very high, and the number of patients has ranked first in the world, but the awareness rate is only 40%, and the treatment rate is 25%, which has a great relationship with our underdiagnosis rate, among which no less than 40% of diabetic patients are missed because they only measure fasting blood sugar. Postprandial blood glucose rises because the pancreas cannot secrete enough insulin to make blood glucose fall, which is a manifestation of diabetes, but why can fasting perform well but postprandial abnormalities? It is because some people can function well when they do not have a meal and the pancreas is not under pressure and there is no load, but once they have a meal and there is a load, the pancreas cannot keep up and the abnormal blood glucose is manifested. Therefore, to diagnose diabetes, a comprehensive examination should be done, of which fasting blood sugar and 2-hour postprandial blood sugar are the two key indicators. For people with less normal blood glucose levels or risk factors, the physical examination must check fasting and postprandial blood glucose levels, and the possibility of diabetes should not be ruled out just because fasting is normal.