Biomarker analysis. ROC curves and AUCs were determined for each metabolite and disease group comparison: TB vs HC (blue), TB-DM vs HC (red) and TB-DM vs TB (green). (A) The three metabolites with the highest AUCs per comparison were combined in a 3-feature model and corresponding multivariate ROC curves were fitted by linear support vector machine algorithm. (B–D) ROC curves and boxplots of the following metabolite ratios are shown: phenylalanine/histidine (Phe/His) (B), kynurenine/tryptophan (Kyn/Trp) (C) and citrulline/arginine (Cit/Arg) (D). Each dot represents an individual patient and the optimal cut-off as determined by Youden’s statistic is displayed as a horizontal dotted line.