Which autoantibody is most specific for rheumatoid arthritis?

• A. Rheumatoid factor
• B. ANA
• C. Anti-CCP
• D. Anti-dsDNA

Answer: (C)

Anti-CCP antibodies (anti-citrullinated protein antibodies) are highly specific for rheumatoid arthritis because they target citrullinated proteins that arise during the inflammatory processes characteristic of RA. Their presence strongly supports the diagnosis and is much less common in other diseases or in healthy individuals.

Rheumatoid factor, while often present in RA, is not specific and can be positive in other autoimmune diseases and even in some healthy older people. ANA is a nonspecific screening marker for autoimmune disease and is not specific for RA, and anti-dsDNA is highly specific for systemic lupus erythematosus rather than RA.

So, among these options, anti-CCP provides the greatest specificity for rheumatoid arthritis, and it can help confirm RA—especially when RF is negative.