Exams and Tests

Many people 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 will be watched closely and receive tests to measure the levels of electrolytes and sugar (glucose) in their blood.

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

A blood glucose test is used to measure 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

A hemoglobin A1c test is recommended for monitoring blood sugar control after treatment has begun because it estimates average blood sugar level over the previous 2 to 3 months. It may be done when a person is diagnosed, and it may be used as a comparison for blood sugar control after treatment starts.

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.²