Table 5. Summary of post-test probability according to the prevalence and predicted positive likelihood ratio.
| Prevalence of culture-positive PTB | Prediction Score | Pre-test odds | LR+ | Post-test odds | Post-test probability | |
| Study population in derivation phase | 3.2%a | 1 | 0.033 | 328.33 | 10.82 | 91.5% |
| Study population in validation phase | 3.6%b | 1 | 0.037 | 328.33 | 12.26 | 92.5% |
| High prevalence | 5.0% | 1 | 0.053 | 328.33 | 17.28 | 94.5% |
| Moderate prevalence | 3.0% | 1 | 0.031 | 328.33 | 10.15 | 91.0% |
| Moderate-to-low prevalence | 1.0% | 1 | 0.010 | 328.33 | 3.32 | 76.8% |
LR+, predicted positive likelihood ratio. The LR+ = 328.33 derived from the equation (sensitivity/1-specificity) with a sensitivity = 98.5% and specificity = 99.7% in derivation phase.
a
The prevalence was calculated based on the culture-positive PTB probability in the derivation phase (132/4140).
b
The prevalence was calculated based on the culture-positive PTB probability in validation phase (147/4105).