Table 3.
Screening performance of parallel testing of serum RPR and serum TPPA for S-NS
| Parallel testing format | Identification of S-NS | Identification of confirmed neurosyphilis | Identification of probable neurosyphilis | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Sensitivity (%) | Specificity (%) | NPV (%) | Sensitivity (%) | Specificity (%) | NPV (%) | Sensitivity (%) | Specificity (%) | NPV (%) | |
| RPR≥1:4, TPPA≥1:2560a | 87.8 | 72.5 | 84.9 | 97.5 | 60.8 | 98.0 | 70.1 | 72.5 | 86.6 |
| RPR≥1:2, TPPA≥1:2560 | 92.6 | 55.6 | 87.6 | 99.2 | 45.7 | 99.1 | 80.6 | 55.6 | 88.4 |
| RPR≥1:4, TPPA≥1:1280 | 93.1 | 58.7 | 89.0 | 99.2 | 47.6 | 99.2 | 82.1 | 58.7 | 89.7 |
| RPR≥1:2, TPPA≥1:1280 | 95.8 | 46.4 | 91.2 | 100.0 | 37.0 | 100.0 | 88.1 | 46.4 | 91.2 |
S-NS symptomatic neurosyphilis, N-NS syphilis/non-neurosyphilis, RPR rapid plasma reagin, TPPA T. pallidum particle agglutination, PPV positive predictive value, NPV negative predictive value
aA positive screening result was defined as either serum RPR titer ≥1:4 or serum TPPA titer ≥1:2560, or both. And by this analogy