In diagnosing rheumatoid arthritis, which laboratory test is commonly used?

• A. RF Factor and ESR
• B. CBC and CMP
• C. ANA and anti-dsDNA
• D. Uric Acid and CRP

Answer: (A)

Rheumatoid arthritis diagnosis commonly uses tests that show autoantibody presence and inflammation. Rheumatoid factor is an autoantibody that’s often found in people with RA, helping to support the diagnosis, though it can be positive in other conditions and even in some healthy individuals. The erythrocyte sedimentation rate measures how fast red blood cells settle in a tube, which rises with inflammation and helps gauge disease activity over time. Using both together provides practical evidence that fits with the typical joint symptoms of RA and aids in monitoring, even though neither test alone is definitive.

Other lab tests like CBC and CMP are general health panels and don’t specifically indicate RA. ANA and anti-dsDNA point toward lupus rather than RA. Uric acid can hint at gout, and CRP is a non-specific inflammatory marker. But RF plus ESR remains the most commonly used initial rheumatoid arthritis lab workup because it directly supports autoimmune involvement and inflammatory activity in the context of compatible joint findings.