Figure 3: ROC curve of OD values for rESAT-6-CFP-10 antigen among pulmonary TB suspects in Ethiopia. This figure shows the sensitivity and 1-specificity of the antigen taking all possible cut-off values. The area under the curve is 0.71 (CI 0.64- 0.78). A cut-off value, 0.21, was selected when senstivity+specifcity-1 is maximum and the sensitivity and specificity became 91.0% and 41.7%, respecively. A: Sensitivity and 1-specificity values corresponding to OD value of 0.21