Sensitivity and specificity of RF isotypes and CCP: single tests and test combinations
| Assays | Sensitivity (%) | Specificity (%) |
|---|---|---|
| CCP2, second generation anti-cyclic citrullinated peptide antibodies; Ig, immunoglobulin; RF, rheumatoid factor. | ||
| IgG-RF | 43.7 | 91.0 |
| IgA-RF | 50.9 | 88.3 |
| IgM-RF | 66.4 | 82.1 |
| CCP2 | 64.4 | 97.1 |
| IgG-/IgA- or IgM-RF | 70.5 | 74.5 |
| IgG-/IgA-/IgM-RF or CCP2 | 80.7 | 73.3 |
| IgG-RF or CCP2 | 72.9 | 89.0 |
| IgA-RF or CCP2 | 73.6 | 86.4 |
| IgM-RF or CCP2 | 79.3 | 80.7 |