Table 2. Diagnostic performance of nucleic acid amplification tests for TB, compared to both the primary and secondary reference standards.
| Index Test Results | Reference Positive(N) | Reference Negative(N) | Percent Sensitivity(95% CI) | Percent Specificity(95% CI) |
| Mycobacterial culture reference standard | 75 | 136 | ||
| MTD | ||||
| Positive | 29 | 7 | 39% (28–51) | 95% (90–98) |
| Negative | 46 | 129 | ||
| Indeterminate | - | - | ||
| secA1 | 24% (15–35) | 95% (90–98) | ||
| Positive | 18 | 7 | ||
| Negative | 57 | 128 | ||
| Indeterminate | - | 1 | ||
| Clinical TB reference standard | 92 | 75 | ||
| MTD | 32% (22–42) | 97% (91–100) | ||
| Positive | 29 | 2 | ||
| Negative | 63 | 73 | ||
| Indeterminate | - | - | ||
| secA1 | 20% (12–29) | 99% (93–100) | ||
| Positive | 18 | 1 | ||
| Negative | 74 | 74 | ||
| Indeterminate | - | - |
Abbreviations: CI, confidence interval; IQR, inter-quartile range; MTD, Gen-Probe Amplified® Mycobacterium Tuberculosis Direct test; secA1, secretory gene A1 target test; TB, tuberculosis.