The calculated predictive values of the field RPR and RST at different active syphilis prevalences
| Prevalence of active syphilis | Test: | 2% | 3% | 5% | 10% | 15% |
|---|---|---|---|---|---|---|
| Probability of syphilis when test is positive | RST | 24.2% | 32.6% | 45.1% | 63.4% | 73.4% |
| Field RPR | 30.5% | 40.0% | 53.2% | 70.5% | 79.2% | |
| Probability of syphilis when test is negative | RST | 0.53% | 0.80% | 1.36% | 2.83% | 4.42% |
| Field RPR | 0.47% | 0.71% | 1.2% | 2.49% | 3.90% |