Type 2 diabetes may cause increased urination, increased thirst, increased appetite, unexpected weight gain or weight loss, blurred vision, skin or vaginal infections, and tiredness. Most people, however, have no symptoms, especially at first.

Your doctor will ask about your medical history and your symptoms and examine you. He or she will test the level of sugar in your blood. Two blood tests may be done to diagnose diabetes. The fasting plasma glucose test (FPG) test is easier, faster, and less expensive to do. A sample of your blood is tested in the morning before you have eaten anything. If this test shows you have a fasting blood sugar of 126 or more, you may be diabetic. Often a second test will be done after you have fasted since your evening meal and all night. If this second test confirms your high blood sugar, your doctor will diagnose type 2 diabetes.
For the oral glucose tolerance test (OGTT), a sample of your blood is taken when you have not eaten anything since the night before. Then you drink a special sugar drink and your blood is tested 2 hours again later. If after 2 hours your blood sugar level is 200 or higher, you are diabetic.