Figure 3

ROC curves of the antibody tests examined. In case of anti-TG2 IgA and IgG as well as anti-DGP IgG non-significant differences of AUC between primary diagnosis (solid black line) and follow-up setting (dashed grey line) were found while in anti-DGP IgA (bottom left) significant AUC differences were detected. For illustrative purposes, optimal cut-off points (with minimal distance to the upper left corner) are designated using correspondingly coloured arrows. Circle segments illustrate that the cut-off points chosen are indeed optimal, the diagonal line in each plot represents the general case of a random guess. Perfect discrimination would result in an ROC curve touching the upper left corner (100% Sensitivity, 100% Specificity). AUC, area under the curve; anti-TG2, anti-tissue transglutaminase; anti-DGP, antibodies against deamidated gliadin peptides.