The Test Sample
What is being tested?
Diabetes-related autoantibodies are proteins produced by the immune system that have been shown to be associated with type 1 diabetes. Testing can detect the presence of one or more of these autoantibodies in the blood.
Type 1 diabetes is a condition characterized by a lack of insulin due to autoimmune processes that destroy the insulin-producing beta cells in the pancreas. Diabetes-related autoantibodies reflect the destruction of beta cells, the loss of beta cell function, and inadequate production of insulin that are features of type 1 diabetes, but they are not thought to be the cause of type 1 diabetes. In contrast, type 2 diabetes primarily results from the body's resistance to the effects of insulin (insulin resistance) and does not involve autoimmune processes.
Type 1 diabetes was previously known as juvenile or insulin-dependent diabetes but has been re-characterized to reflect beta cell destruction. When autoimmune type 1 diabetes is present, one or more of the diabetes autoantibodies will be present in about 95% of those affected at the time of initial diagnosis. With type 2 diabetes, the autoantibodies are typically absent.
Four of the most common diabetes-related autoantibody tests include:
- Islet Cell Cytoplasmic Autoantibodies (ICA)
- Glutamic Acid Decarboxylase Autoantibodies (GADA)
- Insulinoma-Associated-2 Autoantibodies (IA-2A)
- Insulin Autoantibodies (IAA)
For more on these, see The Test tab.
About 5% of all cases of diabetes are type 1 (autoimmune) and the majority of these cases are diagnosed in people younger than 20. Symptoms of diabetes, such as frequent urination, thirst, weight loss, and poor wound healing, emerge when about 80-90% of a type 1 diabetic's beta cells have been destroyed and are no longer able to produce insulin. The body requires daily insulin so that glucose can enter cells and be used for energy production. Without sufficient insulin, cells starve and high blood sugar (hyperglycemia) results. Acute hyperglycemia can cause a diabetic medical crisis and chronic hyperglycemia can damage blood vessels and organs such as the kidneys.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.