Sensitivities and specificities according to the standard and adapted cut offs for RF and three anticitrullinated protein antibodies and the 95% confidence intervals as defined in study population 1
| Test (cut off) | Sensitivity | Specificity |
|---|---|---|
| Values are given as 95% confidence interval. | ||
| Standard cut off | ||
| RF (⩾3.125 U/ml) | 78.6 (71.2 to 86.0) | 80.8 (74.4 to 87.2) |
| Anti-pepA antibodies | 63.6 (54.9 to 72.3) | 100 (98.0 to 100) |
| Anti-pepB antibodies | 54.2 (45.3 to 63.1) | 99.3 (96.8 to 100) |
| Anti-CCP2 antibodies (>25 U/ml) | 75.4 (67.6 to 83.2) | 97.3 (93.8 to 99.1) |
| Adapted cut off | ||
| RF (⩾150 U/ml) | 12.8 (6.7 to 18.9) | 98.6 (95.8 to 99.8) |
| Anti-pepA antibodies | 63.6 (54.9 to 72.3) | 100 (98.0 to 100) |
| Anti-pepB antibodies | 54.2 (45.3 to 63.1) | 99.3 (96.8 to 100) |
| Anti-CCP2 antibodies (⩾42 U/ml) | 73.7 (65.8 to 81.6) | 98.6 (95.8 to 99.8) |