If your doctor thinks that you may have diabetes, he or she will order a couple of blood glucose tests. Blood glucose tests are blood tests that measure how much sugar is in your blood. Usually, they are done first thing in the morning, before you eat or drink anything.

To make a diagnosis of type 2 diabetes, your doctor will use your blood test results and the American Diabetes Association's criteria. He or she also will ask you questions about your medical history and do a physical exam.

If your blood sugar level is above normal but below the level for diabetes, you have prediabetes and are at risk for developing type 2 diabetes. For more information on prediabetes, see the topic Prediabetes.

Other tests

A home blood sugar test or a urine test for sugar are not the best ways to learn whether you have diabetes. However, after you are diagnosed, you may use home blood sugar tests to check your own blood sugar levels.

Along with your home blood sugar tests, your health professional will give you a hemoglobin A1c (glycohemoglobin) test after you start treatment for diabetes. This test finds your average blood sugar level over the previous 2 to 3 months. The A1c test adds to the information from your home blood sugar tests to help you keep track of your blood sugar control.

After you are diagnosed with type 2 diabetes or prediabetes, you may have a thorough exam of your cardiovascular system to check for any heart problems.

Early detection

You can use the American Diabetes Association's risk test for diabetes to see whether you are at risk for developing type 2 diabetes.

If you are age 45 or older, the American Diabetes Association recommends that you be tested for diabetes every 3 years. The United States Preventive Services Task Force (USPSTF) recommends testing for diabetes in people who have either high cholesterol or high blood pressure. Talk with your doctor about your risk factors and how often you need to be tested.

The American Diabetes Association recommends that you be tested more often or begin testing at a younger age if you:⁴

• Have a parent, brother, or sister who has type 2 diabetes.
• Are overweight (have a body mass index, or BMI, of 25 or higher). See the body mass index (BMI) chart for adults or the same chart in metric to determine your BMI.
• Are African American, Hispanic, Native American, Asian American, or Pacific Islander.
• Have prediabetes.
• Have high blood pressure.
• Have high cholesterol.
• Have a history of gestational diabetes or have delivered a baby who weighed 9lb or more.