Figure 2.

Specificity estimates of Xpert MTB/RIF and Xpert MTB/RIF Ultra (Xpert Ultra) for tuberculosis case detection in patients with a tuberculosis treatment history and for different approaches to handling an initial Xpert Ultra trace-positive result

The curves show specificity in participants with tuberculosis history as a function of the time since completion of treatment for the previous tuberculosis episode within 10 years of enrolment (50 cases with treatment more than 10 years earlier were omitted; recoding these 50 cases to be at 10 years did not lead to any noticeable changes in the findings). The results of the Xpert Ultra conditional trace results approach are not shown but would have been directly below the curve for the Ultra without trace. Curves were created using running-line least squares (mean) smoothers with a bandwidth of 0·8.¹⁸