Diabetes

Diagnostics are based upon detection of antibodies against islet cells (ICA) using indirect immunofluorescence. 80 to 90% of the patients with new onset diabetes are positive for such antibodies. As stated earlier, the potential antigens are GAD, IA2 and ZnT8.

• The prevalence of anti-GAD antibodies in patients of IDDM is 60 to 80 percent.
• The prevalence of anti-IA2 antibodies among IDDM patients is 50 to 80% and they are usually associated with younger patients.
• Anti-insulin antibodies also show age dependency. In patients under age five, the prevalence is over 90 percent. These paediatric antibodies can currently be detected with sufficient sensitivity using only RIA.

Antibodies against ZnT8 serve as a good alternative to anti-insulin antibodies. They too are highly popular among the pediatric age group with prevalence stacking at around 70 percent.

Autoantibodies against various antigens in IDDM appear before the first clinical symptoms. Thus, they are considered as markers of pre-diagnostic phase. For an accurate diagnosis, different tests are run in parallel to achieve an overall increased sensitivity and specificity.