Getting a diagnosis of rheumatoid arthritis (RA) can be a difficult process. A firm diagnosis may take some time. In its early stages, RA may resemble other forms of arthritis. No single test can confirm RA. Below are the main steps your doctor will take to help determine if you have RA.
Your doctor will ask about your joint symptoms (pain, tenderness, stiffness, difficulty moving) – how and when they started, if they come and go, how severe they are and if anything makes them better or worse. The number and location of joints involved can also indicate RA; the disease tends to affect the same joint on both sides of the body. However, it is possible for the disease to develop in a single joint.
Your doctor should examine each joint, looking for tenderness, swelling, warmth and painful or limited movement. An overall physical exam may reveal other signs, such as rheumatoid nodules or a low-grade fever.
Blood tests are done to measure inflammation and look for biomarkers, such as antibodies (blood proteins), that are linked with RA.
- Erythrocyte sedimentation rate (ESR, or “sed rate”) and C-reactive protein (CRP) level are markers for inflammation. A high ESR or CRP combined with other clues to RA helps make the diagnosis.
- Rheumatoid factor (RF) is an antibody found in about 80 percent of people with RA over time. Antibodies to cyclic citrullinated peptide (CCP) are found in 60 to 70 percent of people with RA and can exist even before symptoms start. They are, however also found in people without RA.
RA can cause the ends of the bones within a joint to break down. These areas are called erosions. An X-ray, ultrasound, or MRI (magnetic resonance imaging) scan may be done to look for erosions. Their absence doesn’t rule out RA, however. It may mean that RA is in an early stage and hasn’t yet damaged your bones. Imaging results can also help monitor how well treatment is working.