Which laboratory findings are most consistent with rheumatoid arthritis?

• A. Positive RF or anti-CCP antibodies and elevated ESR/CRP.
• B. Negative RF and normal CRP.
• C. Elevated CK.
• D. Elevated ESR with negative RF.

Answer: (B)

Rheumatoid arthritis typically shows autoimmune antibodies together with signs of inflammation. The most characteristic pattern is the presence of rheumatoid factor or anti-CCP antibodies along with elevated inflammatory markers like ESR or CRP. Anti-CCP is particularly specific for RA, so having either RF or anti-CCP plus an elevated ESR/CRP fits RA best because it reflects both autoimmunity and active synovial inflammation.

The other patterns are less consistent with RA. Negative RF with normal CRP would be unlikely in active disease. A markedly elevated CK points more toward muscle disease rather than a joint-centric condition. Elevated ESR with negative RF can occur in seronegative cases, but it lacks the stronger RA-specific antibody evidence that raises diagnostic confidence.