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

• A. RF Factor and ESR
• B. Cholesterol Panel
• C. Blood Glucose
• D. CT Angiography

Answer: (A)

Diagnosing rheumatoid arthritis relies on recognizing an autoimmune inflammatory process, and certain laboratory tests are routinely used to support that clinical picture. Testing for rheumatoid factor and an elevated erythrocyte sedimentation rate are common because they reflect immune activity and inflammation that often accompany RA. Rheumatoid factor is an autoantibody that appears in many RA patients, helping to confirm the inflammatory nature of the disease when the clinical signs fit. ESR measures how quickly red blood cells settle, rising with inflammation and providing a sense of disease activity over time. While RF isn’t perfectly specific and ESR isn’t specific to RA alone, together they reinforce the diagnosis in the right clinical context and are standard parts of the initial workup.

The other tests listed don’t target the autoimmune inflammatory process of RA: a cholesterol panel assesses cardiovascular risk, blood glucose screens for diabetes, and CT angiography images blood vessels.