Comparing the Two Tests
| Feature | Anti-CCP | Rheumatoid Factor (RF) |
|---|---|---|
| Sensitivity for RA | 60–70% | 70–80% |
| Specificity for RA | >95% | ~80% (less specific) |
| Can be positive before symptoms | Yes — up to 10 years before clinical RA | Less common |
| Predicts severity | Yes — positive anti-CCP → more erosive disease | Less useful |
| Other causes of positivity | Rarely — very specific to RA | Infection, other autoimmune diseases, healthy elderly |
Non-RA Causes of Positive RF
- Sjögren's syndrome
- SLE (lupus)
- Infection (subacute bacterial endocarditis, hepatitis C, TB)
- Other connective tissue diseases
- Healthy elderly — up to 5% of those >70 years
- Cryoglobulinaemia
Anti-CCP Before SymptomsAnti-CCP can be positive years before RA manifests clinically. In a first-degree relative of a patient with RA who has joint pain, a positive anti-CCP warrants rheumatology referral even if criteria aren't yet met.
NICE Guidance
The 2018 NICE guideline recommends urgent (within 3 weeks) referral to rheumatology for anyone with persistent synovitis — even if RF and anti-CCP are negative. Clinical features matter most.
What does a positive anti-CCP mean if I don't have symptoms?
A positive anti-CCP with no joint symptoms places you at higher risk of developing RA. Annual monitoring and lifestyle modifications (vitamin D, weight management, smoking cessation) are recommended.
Can I have RA with negative anti-CCP and RF?
Yes — seronegative RA. About 20–30% of RA patients are negative for both markers. Diagnosis is clinical and based on synovitis, pattern of joint involvement, and response to DMARDs.
How quickly does RA need treating after diagnosis?
Early aggressive treatment (within 3–6 months of symptom onset) gives the best outcomes. Methotrexate is first-line. Delays allow joint erosion that cannot be reversed.
What is the DAS28 score?
Disease Activity Score in 28 joints — a composite score of tender joints, swollen joints, ESR/CRP, and patient global assessment. Used to monitor RA activity and guide treatment escalation.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.