TABLE 1

Xpert MTB/RIF and acid-fast bacilli (AFB) sensitivity, specificity, predictive positive value (PPV) and negative predictive value (NPV) for 2148 respiratory specimens for pulmonary tuberculosis diagnosis

SputumBALGastric washing
Subjects n1556348244
Xpert
 Sensitivity185/19794 (0.90–0.97)22/2396 (0.78–1.00)29/3097 (0.83–1.00)
 Specificity1337/135998 (0.98–0.99)320/32598 (0.96–0.99)214/214100 (0.98–1.00)
 PPV185/20789 (0.84–0.93)22/2781 (0.62–0.94)29/29100 (0.88–1.00)
 NPV1337/134999 (0.98–1.00)320/32199 (0.98–1.00)214/21599 (0.97–1.00)
AFB
 Sensitivity119/19760 (0.53–0.67)9/2339 (0.20–0.61)18/3060 (0.41–0.77)
 Specificity1352/135999 (0.99–1.00)323/32599 (0.98–1.00)214/214100 (0.98–1.00)
 PPV119/12694 (0.89–0.98)9/1182 (0.48–0.98)18/18100 (0.81–1.00)
 NPV1352/143095 (0.93–0.96)323/33796 (0.93–0.98)214/22695(0.91–0.97)

Data are presented as n/N or % (95% CI), unless otherwise stated. BAL: bronchoalveolar lavage.