Islet Autoantibodies in Diabetes
- Also Known As:
- Diabetes Autoantibodies
- Diabetes Mellitus Autoantibody Panel
- Formal Name:
- Islet Cell Cytoplasmic Autoantibodies (ICA)|Insulin Autoantibodies (IAA)|Glutamic Acid Decarboxylase Autoantibodies (GADA)|GAD65 Autoantibodies|Insulinoma-Associated-2 Autoantibodies (IA-2A)|Zinc Transporter-8 Autoantibodies (ZnT8A)

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At a Glance
Why Get Tested?
To identify people at increased risk for developing type 1 diabetes or requiring insulin treatment; to aid in the classification of diabetes. Note: testing for islet autoantibodies in non-diabetic individuals Is not advised unless the person is a participant in a research study that requires islet autoantibody testing.
When To Get Tested?
Any time that you have diabetes and your healthcare practitioner cannot clearly determine if you have type 1 diabetes or type 2 diabetes, your health care practitioner may order tests for islet autoantibodies.
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
None
You may be able to find your test results on your laboratory’s website or patient portal. However, you are currently at Testing.com. You may have been directed here by your lab’s website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab’s website or portal, or contact your healthcare practitioner in order to obtain your test results.
Testing.com is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.
The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.
If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.
Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called “normal” values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.
While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are “within normal limits.”
For more information, please read the article Reference Ranges and What They Mean.
What is being tested?
Islet 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. Islet autoantibodies can be present prior to the diagnosis of type 1 diabetes, are usually present at the time of diagnosis, and decrease in frequency over 5 to 10 years following the diagnosis of type 1 diabetes.
Islet autoantibodies are markers of an autoimmune (self-reactive) response to the islets, but islet autoantibodies do not cause type 1 diabetes. Type 2 diabetes primarily results from the body’s resistance to the effects of insulin (insulin resistance) together with declining insulin production 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 absolute insulin deficiency. When autoimmune type 1 diabetes is present, one or more of the islet 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.
Five 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)
- Zinc Transporter-8 Autoantibodies (ZnT8A)
For more on these, see “What does the test result mean?” under Common Questions below.
About 10% of all cases of diabetes are type 1 (autoimmune) and the majority of these cases are diagnosed in people younger than 20. However, type 1 diabetes can develop in people of any age. Symptoms of diabetes, such as frequent urination, thirst, weight loss, and poor wound healing, emerge when about 80-90% of the person’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 crises (either diabetic ketoacidosis or hyperglycemic hyperosmolar state or a combination of the two states). Chronic hyperglycemia can damage large and small blood vessels, nerves, and organs such as the kidneys.
Common Questions
View Sources
Sources Used in Current Review
2017 review performed by Shu-Ling Fan, PhD, DABCC, Medical Director, Clinical Chemistry, Department of Pathology, Boston Medical Center.
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