Sensitivity, specificity and positive predictive value (PPV) of the Determine Syphilis TP rapid test using whole blood in the field, compared to different thresholds of serum rapid plasma reagin (RPR) reactivity and Treponema pallidum haemagglutination assay (TPHA) positive as the gold standard
| Gold standard | ||||||
|---|---|---|---|---|---|---|
| Serum RPR reactive and TPHA positive | Serum RPR ⩾1:8 and TPHA positive | Serum RPR ⩾1:16 and TPHA positive | ||||
| Yes | No | Yes | No | Yes | No | |
| Determine positive in whole blood | 70 | 28 | 16 | 82 | 7 | 91 |
| Determine negative in whole blood | 108 | 3277 | 9 | 3376 | 3 | 3382 |
| Total | 178 | 3305 | 25 | 3458 | 10 | 3473 |
| Sensitivity | 39.3% | 64.0% | 70.0% | |||
| Specificity | 99.2% | 97.6% | 97.4% | |||
| PPV | 71.4% | 16.3% | 7.1% | |||