The ADA suggests everyone over the age of 45—and anyone overweight—get screened for type 2. The most common test is the fasting blood glucose test. After not eating for eight hours, you get your blood sugar checked. If your glucose level is 126 milligrams per deciliter (mg/dL) or higher, you have diabetes, according to the ADA. Blood glucose between 100 and 125 mg/dL is considered prediabetes, meaning you are at risk for the disease. If your numbers are borderline, you may be given an oral glucose tolerance test: You consume sugar and then have your blood levels checked. Some doctors also use the hemoglobin A1C blood test, which shows how your blood sugar levels fluctuate over several months. Your A1C number should be under 7%.