Table 3.
Laboratory results of conventional and molecular tests for the diagnosis of pulmonary and extrapulmonary tuberculosis.
| Diagnostic method | Total | Positive (%) | Negative (%) |
|---|---|---|---|
| Smear (%) | 126 | 10 (7.9) | 116 (92.1) |
| Mycobacteria culture (%) | 175 | 19 (10.9) | 156 (89.1) |
| Xpert MTB/RIF Ultra (%) | 175 | 48 (27.4) | 127 (72.6) |
| Threshold cycle (Ct) a | – | 17.4 (16.2–20.4) | – |
| Rifampicin resistance (%) | 48 | 1 (2.0) | – |
| Cobas MTB (%) | 175 | 45 (25.7) | 130 (74.3) |
| Threshold cycle (Ct) a | – | 29.8 (25.6–31.9) | – |
| Isoniazid resistance (%) | 45 | 2 (4.4) | – |
| Rifampicin resistance (%) | 45 | 1 (2.2) | – |
| Logix Smart MTB (%) b | 175 | 36 (20.6) | 124 (70.9) |
| Threshold cycle (Ct) a | – | 29.4 (26.8–36.8) | – |
a
Median and interquartile range.
b
Logix Smart presented 15 samples with indeterminate results, which were excluded for this analysis.
Ct, cycle threshold; MTB, Mycobacterium tuberculosis.