Doctors use several tools to diagnose rheumatoid arthritis (RA) and rule out other conditions. Generally, your doctor will first ask you to describe your symptoms, when and how they started, and how they've changed. Your doctor will also ask about other medical problems you or members of your family have had. Next, she or he will perform a thorough physical exam and do various lab tests to measure substances in your blood that are associated with RA. Your doctor may also order X-rays or other imaging studies to rule out other causes of joint pain.