Diabetes is diagnosed by venous blood sugar, not urine sugar. First of all, the diagnostic criteria of diabetes: drawing venous blood, fasting blood sugar greater than 7mmol/L, or two hours after meal greater than 11.1mmol/L, or with typical symptoms of thirst, excessive drinking, excessive urination, weight loss, measuring any time of blood sugar greater than 11.1mmol/L, can also diagnose diabetes. The reason why urine glucose is not used as a diagnostic criterion for diabetes is that many patients, who have kidney problems, sometimes have a plus urine glucose even if their venous glucose is normal. In addition, if the blood glucose is very high, such as reaching 10mmol/L or 20mmol/L or more, urine sugar always shows 2-3 plus signs, which cannot accurately determine the condition. Therefore, the above analysis concludes that the diagnosis of diabetes relies on the diagnosis of venous blood glucose, not on urine sugar.