Table 2.
Performance Characteristics of Xpert on sediments and raw sputum samples
| Performance characteristics of Xpert in Presumptive PTB using LJ culture as a reference method (N = 262) | ||||
| Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | P-value |
| Performance characteristics of Xpert on sputum sediments using experimental dilution (1:2) | ||||
| 92 (84–97) | 85 (79–90) | 74 (67–80) | 96 (91–98) | 0.0001 |
| Performance characteristics of Xpert on raw sputa using standard dilution (1:2) | ||||
| 86 (77–93) | 86 (77–93) | 75 (65–83) | 93 (88–96) | 0.001 |
| Incremental values | ||||
| 6 | 1 | 1 | 3 | |
| Performance characteristics of Xpert in HIV Infected presumptive PTB (n = 39) | ||||
| Performance characteristics of Xpert on sputum sediments using experimental dilution (1:2) | ||||
| 100 (81–100) | 82 (60–95) | 81 (64–91) | 100 | 0.0001 |
| Performance characteristics of Xpert on raw sputa using standard dilution (1:2) | ||||
| 88 (64–99) | 86 (65–97) | 83 (59–96) | 91 (70–99) | 0.0001 |
| Incremental values | ||||
| 12 | 4 | 2 | 9 | |
NB: The Xpert MTB/RIF assay have been abbreviated as Xpert