Diabetes is rarely misdiagnosed. The diagnosis of diabetes is based on the symptoms of the diabetic and on blood tests. The symptoms are mainly three more and one less, eating more, drinking more, urinating more and losing weight, but the symptoms rarely appear to be there, and are usually measured by blood tests for high blood sugar. If the fasting blood sugar is greater than or equal to 7.1mmol/L, diabetes can be diagnosed. If the blood sugar two hours after meal is greater than or equal to 11.1mmol/L, it can also be diagnosed as diabetes. If some patients are still not convinced, they can perform OGTT test for final diagnosis, and then do glycated hemoglobin to clarify the diagnosis.