IDO1 and tuberculosis: Finally, as shown in Figure 3G, ROC analysis of chitinase protein (AUC = 0.919; sensitivity 97%, specificity 83%) and IDO protein (Figure 3H) (AUC = 0.735; sensitivity 68%, specificity 74%) showed that chitinase protein had excellent and IDO protein had acceptable sensitivity and specificity in differentiating TB recurrence from controls.