The prevalence of GAD Ab was significantly higher in AITD patients than in control subjects (5.8% vs 2.1%, P = .01), particularly in Graves disease (7.1% vs 2.1%, P = .0019).
It has been reported that anti-GAD antibody (GAD-Ab) persists at high levels for longer duration in subjects with type 1 diabetes and Graves' disease, whereas the prevalence of positive GAD-Ab (1.5%) in 131 non-diabetic subjects with Graves' disease was comparable to that in normal subjects (0.3%, P=0.2012).
In study B we tested (in blind fashion) 89 recoded sample sera or standards that were part of the larger group used in the Second International GAD Antibody Workshop, finding GAD65 autoantibodies in 3.3% of healthy control subjects (1/30), 60% of IDDM patients (18/30), 100% of ICA + nondiabetic subjects (3/3) but in none of 4 nondiabetic patients with Graves disease.