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Anti-CCP & Rheumatoid Factor: Rheumatoid Arthritis Tests

Anti-CCP (anti-cyclic citrullinated peptide) and rheumatoid factor are the two main blood tests for rheumatoid arthritis. Anti-CCP is the more specific and diagnostically powerful of the two.

Written and clinically reviewed by Suman Konda, PharmD, Clinical Pharmacist · Based on peer-reviewed sources · Editorial policy · Not medical advice

Last reviewed and updated: · How we check our content

Anti-CCP specificity
>95% for RA
RF sensitivity
~70–80% for RA
RF specificity
Lower: many other causes
Both positive
Confirms RA with high confidence

Comparing the Two Tests

FeatureAnti-CCPRheumatoid Factor (RF)
Sensitivity for RA60–70%70–80%
Specificity for RA>95%~80% (less specific)
Can be positive before symptomsYes: up to 10 years before clinical RALess common
Predicts severityYes: positive anti-CCP → more erosive diseaseLess useful
Other causes of positivityRarely: very specific to RAInfection, 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.
Joint PainArthritis diagnosis

References

The clinical information on this page is drawn from peer-reviewed sources indexed by the US National Library of Medicine. Links go to the source so you can read it yourself.

  1. Erythrocyte Sedimentation Rate. In: StatPearls. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf NBK557485

Related reading

Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.