According to the American Diabetes Association, a repeat test is recommended before making a diagnosis. For Asian Americans, doing an oral glucose tolerance test (OGTT) may be the best test to confirm the diagnosis. However, this test is not frequently done in the office. Instead, you can get an A1c test, which reflects your estimated average glucose over the past 3 months or you can simply get a fasting glucose. For diagnostic values of each test, please see Diagnosing Diabetes.