Table 1.

Characteristics of the relevant autoantibodies in type 1 diabetes[125-134]

	Antigen	Sensitivity	Specificity	Percent at onset	Annotation
ICA	Islet cells	70%	99%	70%-90%	Single positivity similar predictive; in combination ≥ 3 increasing risk to approximately 90%; age independent
GADA	Glutamic acid decarboxylase (65 kDa)	65%-75%	99%	70%-80%
IA2A	Tyrosine phosphatase-related islet antigen 2	50%-90%	99%	50%-70%
IAA	Proinsulin/insulin	74%	99%	30%-50%	Inverse correlation with age; measurement prior to insulin therapy required
ZnT8	C terminal domain of the zinc transporter 8	65%-75%	99%	60%-80%	Declines rapidly after onset of T1D

IAA: Insulin autoantibody; IA2A: Tyrosine phosphatase-related islet antigen 2 autoantibodies; ICA: Islet cell autoantibodies; GADA: Glutamic acid decarboxylase autoantibodies; T1D: Type 1 diabetes; ZnT8: Zinc transporter 8.