Subgroup analysis
| Subgroup | No of studies | Sensitivity | Specificity | PLR | NLR | AUC |
| Design | ||||||
| Prospective | 3 | – | – | – | – | – |
| Retrospective | 5 | 0.76 (0.66, 0.84) | 0.83 (0.79, 0.86) | 4.4 (3.7, 5.3) | 0.29 (0.20, 0.42) | 0.87 (0.83, 0.89) |
| Region | ||||||
| China | 4 | 0.84 (0.79, 0.89) | 0.83 (0.77, 0.88) | 5.1 (3.6, 7.1) | 0.19 (0.14, 0.26) | 0.87 (0.84, 0.90) |
| Non-China | 4 | 0.64 (0.45, 0.79) | 0.83 (0.80, 0.86) | 3.7 (2.8, 5.0) | 0.44 (0.27, 0.70) | 0.83 (0.80, 0.86) |
| Sample size | ||||||
| <200 | 3 | – | – | – | – | – |
| ≥200 | 5 | 0.79 (0.68, 0.86) | 0.84 (0.80, 0.87) | 4.9 (3.9, 6.2) | 0.26 (0.17, 0.39) | 0.88 (0.84, 0.90) |
| Cut-off | ||||||
| ≤66.7 pg/mL | 4 | 0.80 (0.71, 0.86) | 0.82 (0.77, 0.85) | 4.3 (3.4, 5.4) | 0.25 (0.18, 0.36) | 0.86 (0.83, 0.89) |
| >66.7 pg/mL | 4 | 0.69 (0.47, 0.85) | 0.84 (0.79, 0.89) | 4.4 (2.8, 7.1) | 0.37 (0.19, 0.71) | 0.86 (0.83, 0.89) |
| Publication date* | ||||||
| ≤5 | 4 | 0.80 (0.71, 0.87) | 0.81 (0.78, 0.84) | 4.3 (3.6, 5.2) | 0.24 (0.16, 0.36) | 0.85 (0.82, 0.88) |
| >5 | 4 | 0.69 (0.48, 0.84) | 0.86 (0.81, 0.90) | 4.9 (2.9, 8.4) | 0.36 (0.19, 0.69) | 0.87 (0.84, 0.90) |
| Clinical subtype | ||||||
| ANS | 1 | – | – | – | – | – |
| SNS | 2 | – | – | – | – | – |
| Unclassified | 5 | 0.81 (0.70, 0.89) | 0.85 (0.80, 0.89) | 5.4 (4.0, 7.3) | 0.22 (0.14, 0.35) | 0.90 (0.87, 0.92) |
| HIV status | ||||||
| Negative | 4 | 0.84 (0.79, 0.89) | 0.83 (0.77, 0.88) | 5.1 (3.6, 7.1) | 0.19 (0.14, 0.26) | 0.87 (0.84, 0.90) |
| Positive | 1 | – | – | – | – | – |
| Not mentioned | 3 | – | – | – | – | – |
*Publication date ≤5 means that the year of publication is no more than 5 years up to 1 May 2023, while >5 means that the year of publication is more than 5 years up to 1 May 2023.
ANS, asymptomatic neurosyphilis; AUC, area under the curve; CXCL13, CXC motif chemokine 13; NLR, negative likelihood ratio; PLR, positive likelihood ratio; SNS, symptomatic neurosyphilis.