Table 3. Additional yield with regards to TB diagnosis and rifampicin resistance detection of Xpert compared to fluorescence smear microscopy.
| Risk group | Xpert tests done | Additional TB diagnostic yield | Additional diagnosis of Rif-R | |||
| N | % increase | NNT | N | NNT | ||
| Presumptive or confirmed HIV (smear/Xpert in parallel) n = 319 | ||||||
| smear(+) | 27 | - | - | - | 2 | 14 |
| smear(−) | 292 | 11 | 41% (38/27) | 27 | 0 | - |
| Presumptive MDR-TB (smear/Xpert in parallel) n = 1.507 | ||||||
| smear(+) | 94 | - | - | - | 6 | 16 |
| smear(−) | 1.414 | 45 | 48% (139/94) | 32 | 0 | - |
| Smear(-) with persisting symptoms (Xpert as add-on) n = 125/7.933 smear(-) | ||||||
| smear(+) | 542 | - | - | - | - | - |
| smear(−) | 7.933 | - | - | - | - | - |
| 2nd round smear(−) | 125 | 5 | 1% (547/542) | 26 | 0 | - |
Smear(+): smear-positive; smear(−): smear-negative; HIV: human immuno-deficiency virus; NNT = number needed to test; Rif-R: rifampicin resistance; MDR-TB:multidrug-resistant tuberculosis.