A blood test called the rheumatoid arthritis (RA) test is used to identify rheumatoid arthritis, a disorder in which the body's immune system produces joint pain, swelling, and stiffness. Rheumatoid Factor (RF), Anti-CCP, and inflammation tests like ESR and CRP are common testing. These tests assist medical professionals in determining whether rheumatoid arthritis may be the cause of joint discomfort, although the diagnosis also relies on physical examination and symptoms.