Diabetes-related Autoantibodies

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Also known as: Islet 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; ICA512 Autoantibodies; Protein Tyrosine Phosphatase-like Autoan
Related tests: Glucose; Insulin

At a Glance

Why Get Tested?

After a diagnosis of diabetes is made, to help distinguish autoimmune type 1 diabetes from type 2 diabetes

When to Get Tested?

When a person is first diagnosed with diabetes to help determine whether their diabetes is autoimmune-related; when a diabetic person who is treated with diet or drugs has great difficulty maintaining normal or near-normal blood sugar levels and is suspected of having type 1 instead of type 2 diabetes

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?


The Test Sample

What is being tested?

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 autoantibody tests are a group of tests that detect the presence of one or more autoantibodies that have been shown to be associated with type 1 diabetes. These 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. They are not thought to be the cause of type 1 diabetes. In contrast, type 2 diabetes primarily results from insulin resistance and does not involve autoimmune processes.

About 10% of all cases of diabetes are type 1 (autoimmune), and the majority of these cases are diagnosed in patients 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.

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 Autoantiboidies (IAA)

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.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Hussain, A. and Vincent, M. (Updated 2009 July 2). Diabetes Mellitus, Type 1. eMedicine On-line information]. Available online at http://emedicine.medscape.com/article/117739-overview through http://emedicine.medscape.com. Accessed January 2010.

Titus, K. (2009 August). Diabetes markers—closer than you think? CAP Today [On-line information]. Available online through http://www.cap.org. Accessed January 2010.

(2008 May). Overview of Diabetes in Children and Adolescents. National Diabetes Education Information [On-line information]. Available online at http://ndep.nih.gov/media/diabetes/youth/youth_FS.htm through http://ndep.nih.gov. Accessed January 2010.

S4 Pagana, K. D. & Pagana, T. J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 355-356.

Clarke, W. and Dufour, D. R., Editors (© 2006). Contemporary Practice in Clinical Chemistry: AACC Press, Washington, DC. Pp 292-293.

Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 620-621, 630-631.

Kronenberg, H. et. al. (© 2008). Williams Textbook of Endocrinology, 11th Edition: Saunders Elsevier, Philadelphia, PA. Pp 1399.

Kasper DL, Braunwald E, Fauci AS, Hauser SL, Longo DL, Jameson JL eds (2005). Harrison's Principles of Internal Medicine, 16th Edition, McGraw Hill, Pg 2156.

Matti Ankelo, et al. Time-Resolved Immunofluorometric Dual-Label Assay for Simultaneous Detection of Autoantibodies to GAD65 and IA-2 in Children with Type 1 Diabetes. Clinical Chemistry. 2007;53:472-479.

Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. McPherson R, Pincus M, eds. Philadelphia, PA: Saunders Elsevier: 2007, 956.

Sources Used in Previous Reviews

Maclaren, N. and Marker, J. (2002 December). Guidelines & Recommendations for Laboratory Analysis in the Diagnosis & Management of Diabetes Mellitus. Weill College of Medicine of Cornell University, NACB Laboratory Medicine Practice Guidelines [On-line information]. Available online at http://www.nacb.org/temporary/Maclaren2.htm through http://www.nacb.org.

Kimpimäki, T. et. al. (2000). Disease-Associated Autoantibodies as Surrogate Markers of Type 1 Diabetes in Young Children at Increased Genetic Risk. Journal of Clinical Endocrinology & Metabolism Vol 85 No. 3 1126-1132 [On-line information]. Available online at http://jcem.endojournals.org/cgi/content/full/85/3/1126 through http://jcem.endojournals.org.

Borg, H. et. al. (2001). High Levels of Antigen-Specific Islet Antibodies Predict Future ß-Cell Failure in Patients with Onset of Diabetes in Adult Age. The Journal of Clinical Endocrinology & Metabolism 86 (7): 3032. (2001) [On-line journal]. Available online at http://jcem.endojournals.org/cgi/reprint/86/7/3032 through http://jcem.endojournals.org.

Achenbach, P. et. al. (2004). Stratification of Type 1 Diabetes Risk on the Basis of Islet Autoantibody Characteristics. Diabetes 53:384-392 [On-line journal]. Available online at http://diabetes.diabetesjournals.org/cgi/content/full/53/2/384 through http://diabetes.diabetesjournals.org.

(© 2005). Glutamic Acid Decarboxylase (GAD) Antibody. ARUP's Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.arup-lab.com/guides/clt/tests/clt_a287.jsp#1149613 through http://www.arup-lab.com.

(© 2005). Islet Cell Antibody, IgG. ARUP's Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.arup-lab.com/guides/clt/tests/clt_a25b.jsp#1153005 through http://www.arup-lab.com.

(© 2005). IA-2 Antibody. ARUP's Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.arup-lab.com/guides/clt/tests/clt_alpb.jsp#2441172 through http://www.arup-lab.com.

Dupré, J. & Mahon, J. (2000 August). Diabetes-Related Autoantibodies and the Selection of Subjects for Trials of Therapies to Preserve Pancreaticß-Cell Function in Recent-Onset Type 1 Diabetes. Diabetes Care, (23): 8 [On-line information]. Available online through http://care.diabetesjournals.org.

Rewers, M. (2005 October, Updated). Type I Diabetes: Molecular, Cellular, and Clinical Immunology, Chapter 9 Epidemiology of Type I Diabetes. Barbara Davis Center for Childhood Diabetes, UCDHSC [On-line information]. Available online at http://www.uchsc.edu/misc/diabetes/oxch9.html through http://www.uchsc.edu.

Eisenbarth, G. (2003 November). Chapter 11 Prediction of Type I Diabetes: The Natural History of the Prediabetic Period. Type I Diabetes: Molecular, Cellular, and Clinical Immunology, Barbara Davis Center for Childhood Diabetes, UCDHSC [On-line information]. Available online at http://www.uchsc.edu/misc/diabetes/oxch11.html through http://www.uchsc.edu.

Winter, WE. Diabetes disease management: differentiating type 1 and type 2 diabetes. Clinical Laboratory News. 2005; 31(7):14-16.

Winter, W.E. Autoimmune Disorders that Influence Carbohydrate Metabolism (Chapter 24). In: Clinical and Laboratory Evaluation of Human Autoimmune Diseases. Nakamura R.M., Keren, D.F., Bylund D.J. (eds): ASCP Press, Chicago, 2002, Pp:345-372.

Winter, W.E. Autoimmune Endocrinopathies. In: Pediatric Endocrinology, Fourth Edition, F. Lifshitz (ed): Marcel Dekker, Inc., New York, New York, 2003, Pp 683-720.

Winter, W.E. and Signorino, M. R. Immunologic Disorders in Infants and Children (5th edition). In: Autoimmune Endocrinopathies. E.R. Stiehm (ed), W.B. Saunders Company, Philadelphia, Pennsylvania, 2004, Pp 1179-1221.

William Winter, M.D. Professor of Pathology and Pediatrics, University of Florida School of Medicine, Gainesville, FL.