Table 2.

RIF assay results of Hain, Xpert, and RT MTB RIF/INH compared against DST

Assay results	DST
Hain	Resistant	Sensitive
RIF resistant	27	1
RIF sensitive	5	89
Hain RIF sensitivity −84.4% (27/32) [95% CI 67.2%–94.7%]
Hain RIF specificity −98.9% (89/90) [95% CI 94.0%–100.0%]
Hain RIF PPV −96.4% (27/28) [95% CI 81.7%–99.9%]
Hain RIF NPV −94.7% (89/94) [95% CI 88.0%–98.3%]
Xpert
RIF resistant	28	0
RIF sensitive	4	90
Xpert RIF sensitivity −87.5% (28/32) [95% CI 71.0%–96.5%]
Xpert RIF specificity −100% (90/90) [95% CI 96.0%–100.0%]
Xpert RIF PPV −100.0% (28/28) [95% CI 87.7%–100.0%]
Xpert RIF NPV −95.7% (90/94) [95% CI 89.5%–98.8%]
RT MTB RIF/INH
RIF resistant	28	0
RIF sensitive	4	90
RT MTB RIF/INH RIF sensitivity −87.5% (28/32) [95% CI 71.0%–96.5%]
RT MTB RIF/INH RIF specificity −100% (90/90) [95% CI 96.0%–100.0%]
RT MTB RIF/INH RIF PPV −100.0% (28/28) [95% CI 87.7%–100.0%]
RT MTB RIF/INH RIF NPV −95.7% (90/94) [95% CI 89.5%–98.8%]

Abbreviations: RT MTB RIF/INH, RealTime MTB RIF/INH Resistance Assay; MTB, Mycobacterium tuberculosis; RIF, rifampicin; INH, isoniazid; DST, drug sensitivity testing; PPV, positive predictive value; NPV, negative predictive value.