Table 3.
Performance of the genotype MTBC assay in detecting M. tuberculosis from direct sputum samples
| Genotype MTBC assay, n % (95% confidence interval) |
||||||||
|---|---|---|---|---|---|---|---|---|
| Reference methods | Positive | Negative | Sensitivity | Specificity | PPV | NPV | Accuracy | Cohen’s kappa |
| Smear Microscopy | ||||||||
| Positive | 23 | 3 | 68 (49–83) | 92 (78–98) | 88 (69–97) | 77 (62–87) | 81 (70–89) | 61 (43–79) |
| Negative | 11 | 36 | ||||||
| LJ culture | ||||||||
| Positive | 33 | 3 | 97 (83–100) | 92 (78–98) | 92 (66–99) | 97 (84–100) | 95 (86–98) | 89 (79–99) |
| Negative | 1 | 36 | ||||||
| Genotype MTBDRplus/sl | ||||||||
| Positive | 34 | 4 | 100 (87–100) | 90 (75–97) | 89 (74–97) | 100 (88–100) | 95 (86–98) | 89 (79–99) |
| Negative | 0 | 35 | ||||||
LJ, Lowenstein–Jensen solid media; MTBDRplus/sl, genotype MTBDRplus or MTBDRsl assays for detecting M. tuberculosis complex and drug resistance; NPV, negative predictive value; PPV, positive predictive value.