Numerous epidemiologic studies have shown that people with 1 or more first-degree relatives who are affected with diabetes are 2 to 6 times as likely to have the disease compared with people who have no affected relatives.
In the absence of these risk factors, the American Diabetes Association recommends that testing for diabetes should begin at age 45 years. If results are normal, the test should be repeated after 3 years or sooner, depending on risk status.
Fasting capillary blood glucose
Random blood glucose
Plasma glucose value 2 hours after a 75g oral load of glucose