Diagnostic value of RF, anti-CCP and anti-RA33 autoantibodies. Data in the overall patient population
| Autoantibodies | RA | Non-RA | Sensitivity | Specificity | PPV |
|---|---|---|---|---|---|
| (n = 102) | (n = 98) | (%) | (%) | (%) | |
| PPV, positive predictive value. | |||||
| High titre RF (⩾50 U/ml) and anti-CCP both showed high specificity and comparable sensitivity, whereas low titre RF occurred with similar frequency in the RA and in the non-RA group. | |||||
| RF (>20 U/ml) (n) | 56 | 11 | 55 | 89 | 84 |
| High titre RF (⩾50 U/ml) (n) | 46 | 4 | 45 | 96 | 92 |
| Anti-CCP (n) | 42 | 2 | 41 | 98 | 96 |
| Anti-RA33 (n) | 29 | 10 | 28 | 90 | 74 |