Gene expression and ROC curves for mRNA increases in IFN-γ and TNF-α in ESAT-6-activated PBMC from Mtb-infected individuals (TB + LTBI) and TST– donors. A and C, PBMC from Mtb-infected individuals (TB patients, n = 30; LTBI, n = 24), or TST– controls (n = 10) were cultured with ESAT-6 for 15 h, and mRNAs for IFN-γ and TNF-α were measured by qPCR. Horizontal bar, Median fold increase for each group. B and D, ROC curves for discriminating Mtb infected from TST– individuals. The calculated AUC is 0.81 (95% confidence interval (CI), 0.70–0.92) for IFN-γ and 0.77 (95% CI, 0.62–0.90) for TNF-α.