Exams and Tests

Some people—especially children, teenagers, and young adults—are not diagnosed with type 1 diabetes until they are admitted to a hospital for diabetic ketoacidosis (DKA). This life-threatening condition occurs when ketones, or fatty acids, are produced as the body burns fat and muscle instead of glucose for fuel. DKA develops in people who have type 1 diabetes (and some people who have type 2 diabetes) when their blood sugar is very high.

During hospitalization, people with DKA are watched closely and receive tests to measure the levels of electrolytes and sugar (glucose) in their blood.

If a person is not in ketoacidosis, the American Diabetes Association's criteria for symptoms, a medical history, a physical exam, and blood tests are used to diagnose type 1 diabetes.

These blood tests include:

• Hemoglobin A1c, a test that estimates your blood sugar over the past 2 to 3 months.
• Blood glucose test, a test that measures your blood sugar. This test is done preferably after fasting, but it can be done at any time, even if you have recently eaten.

Other tests that may suggest diabetes

You may need a thyroid-stimulating hormone (TSH) test when type 1 diabetes is diagnosed and then every 1 to 2 years. This test checks for thyroid problems, which are common among people with diabetes.

Neither a home blood sugar test nor a urine test for sugar is recommended to screen for or diagnose diabetes.

Early detection

Screening for type 1 diabetes is not recommended by the American Diabetes Association. Such screening would include testing everyone for islet cell antibodies. This test can show if a person is more likely to get type 1 diabetes.

People who are found to have islet cell antibodies may be able to participate in studies about preventing type 1 diabetes. These people need to be referred to a medical center conducting a type 1 diabetes prevention study.³