S100A12 and juvenile idiopathic arthritis: S100A12 had 100.0% specificity (95% CI: 88.1%—upper limit is not applicable) and 46.3% sensitivity (95% CI: 35.0–57.8%) as a diagnostic JIA biomarker for cut-off level 10.73 ng/ml with AUC 0.787 (95% CI: 0.701–0.873).