Table 4 Hypothetical Predictive Values of Xpert detection of MTBc vs. MTB Culture
Prevalence of MTB culture positive | Probability of MTB culture positive among | Probability of MTB culture negative among | |
|---|---|---|---|
Xpert MTB detected AFB Smear Pos. | Xpert MTB detected AFB Smear Neg. | Xpert MTB not detected | |
1% | 82.9 | 14.4 | 99.9 |
2% | 90.8 | 25.4 | 99.9 |
3% | 93.7 | 34.1 | 99.8 |
4% | 95.2 | 41.0 | 99.7 |
5% | 96.2 | 46.8 | 99.7 |
10% | 98.2 | 65.0 | 99.3 |
11.8% | 98.5% | 69.1% | 99.2% |
20% | 99.2 | 80.7 | 98.5 |
40% | 99.7 | 91.8 | 96.1 |
50% | 99.8 | 94.4 | 94.2 |