CD38 and tuberculosis: Using receiving operating characteristic (ROC) curve analysis, co-expression of CD38 and HLA-DR on ESAT-6/CFP-10 responding total cytokine-producing CD4+ T-cells had a high sensitivity for discriminating HIV+TB (100%, 95% CI 70–100) and HIV−TB (100%, 95% CI 70–100) from latent TB with high specificity (100%, 95% CI 68–100 for HIV−TB) at a cut-off value of 5% and 13%, respectively.