Table 1

Islet autoantibody status during changes in GAD-65 autoantibody assay methods

Before July 2007August 2007–December 2011After January 2012p Value
Sample size (T1D/T2D)81 (77/4)167 (157/10)68 (62/6)0.61
GAD-65 assayIn house ELISAIndirect immunofluorescenceStandardised ELISA
GAD-65 +ve (%)18.413.866.7<0.001
ICA +ve (%)50.638.245.00.18
IAA +ve (%)26.524.021.90.88
Positivity for any antibody (%)64.649.172.20.002
T2D with antibody positivity (%)
T1D with antibody negativity (%)32.444.225.80.09
  • IAA, insulin autoantibody; ICA, islet cell autoantibody; GAD, glutamic acid decarboxylase; T1D, type 1A diabetes; T2D, type 2 diabetes.