Table 2.
Diagnostic value of the biological items
| Sensitivity | Specificity | PPV | NPV | |
|---|---|---|---|---|
| Anti-SSA or -SSB positivity |
61.0% |
100% |
100% |
79.9% |
| Anti-SSA positivity |
61.0% |
100% |
100% |
79.9% |
| Anti-SSB positivity |
32.5% |
100% |
100% |
66.7% |
| ANA ≥1:320 |
80.5% |
58.7% |
59.0% |
80.3% |
| ANA ≥1:640 |
70.1% |
81.7% |
74.0% |
78.7% |
| IgM-RF positivity |
45.5% |
79.8% |
62.5% |
66.4% |
| IgA-RF positivity |
41.6% |
95.2% |
86.5% |
68.8% |
| Gammaglobulins ≥14 g/L |
46.8% |
92.3% |
81.8% |
70.1% |
| IgG ≥14 g/L |
49.4% |
91.3% |
80.9% |
70.9% |
| B-cell ratio ≥5 |
53.2% |
82.7% |
69.5% |
70.5% |
| ACR criteria serologic item | 63.6% | 93.7% | 87.5% | 77.6% |
PPV, positive predictive value; NPV, negative predictive value; ANA, antinuclear antibodies; Ig, immunoglobulin; RF, rheumatoid factor; American College of Rheumatology (ACR) criteria serologic item: (anti-SSA/B or (ANA ≥1:320 + IgM-RF)).