Table 3.
Culture results of patients with different acid-fast bacilli smear and Xpert MTB/RIF status.
| Culture | AFB+/Xpert+ | AFB+/Xpert- | AFB-/Xpert+ | AFB-/Xpert- | Total |
|---|---|---|---|---|---|
| MTB | 44 | 1 | 137 | 45* | 227 |
| NTM | 0 | 6† | 0 | 15‡ | 21 |
| Nocardia | 0 | 0 | 0 | 3 | 3 |
| Negative | 7† | 0 | 79¶ | 1,707 | 1,793 |
| Total | 51 | 7 | 216 | 1,770 | 2,044 |
A total of 2,044 patients had BALF and/or sputum AFB smear, culture, Xpert assays, and peripheral blood mononuclear cell T-SPOT performed simultaneously. For strict comparison, only the first AFB smear and Xpert test results were used in the analysis. Culture results were per-patient results (i.e., MTB positivity was defined as at least one of the BALF and/or sputum specimens having one positive culture result for M. tuberculosis. A similar approach was used to define active NTM and Nocardia infections). *None of them were clinically diagnosed as having active tuberculosis. †All of them were clinically diagnosed as having definite or probable tuberculosis. ‡None of them were clinically diagnosed as having NTM infections. ¶Six of them had no tuberculosis-related diagnosis. AFB, acid-fast bacilli; AFB+, AFB smear positive; AFB–, AFB smear negative; Xpert. Xpert MTB/RIF; Xpert+, Xpert positive; Xpert–, Xpert negative; MTB, M. tuberculosis; NTM, nontuberculous mycobacteria; T-SPOT, T-SPOT.TB; BALF, bronchoalveolar lavage fluid.