How a diagnosis is made

Getting an accurate diagnosis is an important step toward taking charge of rheumatoid arthritis (RA). To diagnose RA, rheumatologists look at all the information you provide through medical history and physical examinations, as well as blood tests, X-rays or other procedures.

What the visit with your rheumatologist may involve

Since lab tests alone cannot pinpoint RA, rheumatologists will first use valuable information from you by performing a thorough medical history and physical exam. Lab tests and X-rays can then provide further insight and rule out other conditions.

Medical history. The rheumatologist will ask questions about symptoms you’re experiencing, such as the location and severity of pain and when symptoms usually occur. During this step, be specific. Sharing as much information as possible can help your doctor make the right treatment decisions.

Physical exam. A thorough physical exam is usually the next step of diagnosis and perhaps the most telling. Your doctor will examine each joint for common signs of RA, including swelling, tenderness and pain when in motion, as well as any limited motion and long-term damage. He or she will also note how many joints are affected. This is called a joint count, and it can help your doctor measure the severity of your condition, monitor your symptoms and predict the course RA will take.

Lab tests. After gathering specific information from you, the rheumatologist will then turn to lab tests for further insight and to rule out other possible diseases. Here are some of the things that the rheumatologist may look for when running tests:

• C-reactive protein (CRP). This substance in the body indicates inflammation. As the level of inflammation rises, so does the level of CRP. Studies have shown that people with high levels of CRP over a long period of time also have more severe joint damage.
• Erythrocyte sedimentation rate, also referred to as ESR or "sed rate". Most people with RA have an elevated ESR. A person with severe RA will generally have a higher ESR than one with less severe RA.
• Rheumatoid factor (RF) is another substance that can indicate the presence of RA. When the immune system attacks itself like it does in RA, the body produces RF. About 75% of people with RA are RF positive.
• Cyclic citrullinated peptide (CCP). A person with RA will have an unusually large amount of a substance called citrulline in their blood. CCP sees citrulline as a threat, and works to fight against it.
• Antinuclear antibody (ANA). This test is usually given to people who are experiencing new symptoms of RA, in order to rule out other autoimmune diseases.

Your rheumatologist may also take X-rays to check for swelling of soft tissues and loss of bone density around affected joints and bone scans to detect inflammation. Magnetic resonance imaging (MRI) and joint ultrasound are also diagnostic tools that can detect inflammation and signs of synovitis, or inflammation of the lining of the joint.

Playing your part

Remember, the information gathered during these steps is critical and will continue to prove valuable in future office visits as your doctor monitors your function, medications and your well-being. You can play your part by learning all you can about RA and keeping close track of every symptom you experience, even if it seems unrelated. This way, you can arrive at your appointments prepared with the information necessary for your doctor to prescribe the right treatment and to help you on your way to better living with RA.

Next section — Treating RA