Anti-CCP antibody vs Rheumatoid factor
How to tell Anti-CCP antibody and Rheumatoid factor apart when a board question makes them look alike.
Anti-CCP is the more specific RA antibody; RF is sensitive-ish but nonspecific IgM against IgG Fc.
Side by side
Anti-CCP is more specific for rheumatoid arthritis and predicts erosive disease in symmetric inflammatory MCP/PIP arthritis.
Rheumatoid factor is IgM against Fc portion of IgG and is less specific, appearing in RA, Sjogren, infections, and other inflammatory states.
Anti-CCP is more specific for rheumatoid arthritis and predicts erosive disease in symmetric inflammatory MCP/PIP arthritis.
Rheumatoid factor is IgM against Fc portion of IgG and is less specific, appearing in RA, Sjogren, infections, and other inflammatory states.
About 95% specific for rheumatoid arthritis; can be positive years before symptoms; predicts erosive disease.
IgM against the Fc portion of IgG; sensitive but also positive in Sjogren, hepatitis C, endocarditis, and healthy older adults.
The repair move
Before naming the answer, force the stem through the separator: Anti-CCP is the more specific RA antibody; RF is sensitive-ish but nonspecific IgM against IgG Fc.
Try a free question
CoreA 42-year-old woman has 4 months of symmetric polyarthritis of the MCP and PIP joints with morning stiffness lasting 2 hours. She has noticed swan-neck deformities developing. Hand X-rays show periarticular erosions. Which serologic test is MOST SPECIFIC for the diagnosis?
Show answer and explanation
Answer: A. Anti-cyclic citrullinated peptide (anti-CCP) antibody. Anti-CCP antibodies are more specific (95%) and somewhat less sensitive (70%) than rheumatoid factor for rheumatoid arthritis. Anti-CCP positivity predicts erosive disease and worse prognosis. RA criteria use both anti-CCP and RF as serologic markers.
Why the other choices are tempting
- B. RF is sensitive but not specific (positive in Sjogren, lupus, hepatitis C, infective endocarditis, and even healthy older adults).
- C. ANA is sensitive but not specific for SLE.
- D. Anti-dsDNA is specific for SLE and tracks renal activity.
- E. Anti-Smith is specific for SLE.
Flashcards
Tap a card to flip it.
What clue supports Anti-CCP antibody?
Choose Anti-CCP antibody when the stem gives this pattern: Anti-CCP is more specific for rheumatoid arthritis and predicts erosive disease in symmetric inflammatory MCP/PIP arthritis.
What clue supports Rheumatoid factor?
Choose Rheumatoid factor when the stem gives this contrasting pattern: Rheumatoid factor is IgM against Fc portion of IgG and is less specific, appearing in RA, Sjogren, infections, and other inflammatory states.
Quick answers
What is the fastest way to tell Anti-CCP antibody from Rheumatoid factor?
Anti-CCP is the more specific RA antibody; RF is sensitive-ish but nonspecific IgM against IgG Fc.
What is the key clue for Anti-CCP antibody?
Anti-CCP is more specific for rheumatoid arthritis and predicts erosive disease in symmetric inflammatory MCP/PIP arthritis.
What is the key clue for Rheumatoid factor?
Rheumatoid factor is IgM against Fc portion of IgG and is less specific, appearing in RA, Sjogren, infections, and other inflammatory states.