Table 1.
Comparison of the Abbott RealTime MTB RIF/INH Resistance assay to the indirect DST results for RIF and INH (sample results [n =99])
| Indirect DST | |||||
|---|---|---|---|---|---|
| Rifampicin | Isoniazid | ||||
| Resistant | Susceptible | Resistant | Susceptible | ||
| Abbott RealTime MTB RIF/INH | Resistant | 26 (96.3%) | 0 (0%) | 41 (78.8%) | 0 (0%) |
| Susceptible | 1 (3.7%) | 72 (100%) | 11 (21.2%) | 47 (100%) | |
| Sensitivity: 96.3% (95%CI 87.3%–100%) Specificity: 100% (95%CI 99.3%–100%) PPV: 100% (95%CI 99.1%–100%) vs 100% (95%CI 98.3%–100%) NPV: 98.6% (95%CI 95.3%–100%) |
Sensitivity: 78.8% (95%CI 66.8%–90.9%) Specificity: 100% (95%CI 98.9%–100%) PPV: 100% (95%CI 98.8–100%) NPV: 81.0% (95%CI 70.1%–92.0%) |
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Abbreviations: MTB, Mycobacterium tuberculosis; RIF, rifampicin; INH, isoniazid; DST, drug-susceptibility testing; PPV, positive predictive value; NPV, negative predictive value.