What is the role of islet-cell (IA2) levels in the diagnosis of type 1 diabetes mellitus (DM)?

Updated: Sep 13, 2019
  • Author: Romesh Khardori, MD, PhD, FACP; Chief Editor: George T Griffing, MD  more...
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Answer

Islet-cell (IA2), anti-GAD65, and anti-insulin autoantibodies can be present in early type 1 but not type 2 DM. Measurements of IA2 autoantibodies within 6 months of diagnosis can help differentiate between type 1 and type 2 DM. These titers decrease after 6 months. Anti-GAD65 antibodies can be present at diagnosis of type 1 DM and are persistently positive over time. (See also Type 2 Diabetes Mellitus.)

Testing for islet autoantibodies can substitute for expensive genetic testing in those patients suspected of having maturity-onset diabetes of the young (MODY). The prevalence of these antibodies is the same in patients with MODY as in the healthy population. A positive test for positive islet autoantibodies makes MODY highly unlikely. [72]


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