Table 2.
Detection efficacy of Mycobacterium tuberculosis identification by nucleic acid-based MALDI-TOF MS compared with MGIT 960 culture (N = 100).
| A. Contingency | |||
|---|---|---|---|
| MALDI-TOF MS result | MGIT 960 culture | Total | |
| Positive | Negative | ||
| Positive | 65 | 12 | 77 |
| Negative | 2 | 21 | 23 |
| Total | 67 | 33 | 100 |
| B. Performance metrics | ||
|---|---|---|
| Metric | Value | 95% confidence interval |
| Sensitivity | 97.01% | 89.63–99.64% |
| Specificity | 63.64% | 45.12–79.60% |
| PPV | 84.42% | 74.05–91.71% |
| NPV | 91.30% | 71.96–98.93% |
| Accuracy | 86.00% | 77.63–92.13% |
| Kappa (κ) | 0.619 | 0.454–0.784 |
Statistical test: McNemar’s χ2 = 15.625, p < 0.001.
PPV, positive predictive value; NPV, negative predictive value. MGIT 960 culture was used as the gold standard. Confidence intervals were calculated using the Wilson score method. Analysis focused on MTB detection specifically (n = 100 patients; 67 MGIT 960 positive, 77 MALDI-TOF MS positive including 71 MTB and 6 NTM).