Diagnostic performance of the assays at manufacturers’ and optimal decision levels.
| Assay | AUC % (95% CI) | Manufacturers’ Cutoff | Optimal Cutoff | |||||
|---|---|---|---|---|---|---|---|---|
| Cutoff | Sn (%) | Sp (%) | Cutoff | Sn (%) | Sp (%) | Optimal Sn + Sp | ||
| RF (IU/ml) | 80.8 (74.2–87.3) | 15 | 67.8 | 91.6 | 159.4 | |||
| Anti-MCV (U/ml) | 71.9 (64.4–79.5) | 20 | 49.8 | 91.6 | 82.3 | 45.2 | 97.6 | 142.8 |
| Anti-CCP2 (U) | 82 (75.8–88.3) | 20 | 60.2 | 98.8 | 159 | |||
| AxSYM anti-CCP (U/ml) | 89.1 (84.3–93.8) | 5 | 80.6 | 84.3 | 164.9 | |||
| Anti-CCP3 (U) | 86.7 (81.6-91.9) | 20 | 61.3 | 97.6 | 11.7 | 67.7 | 92.8 | 160.5 |
AUC: area under the curve; CI: confidence interval; Sn: sensitivity; Sp: specificity. Optimal cutoff was determined by the maximal sum of sensitivity and specificity value for each assay. Assays missing optimal cutoff value performed optimally at the manufacturer’s cutoff limit.