There is no single test for rheumatoid arthritis (RA). To help diagnose and treat the condition, your doctor will ask about your symptoms, medical history, and risk factors; perform a physical exam; and run one or more of following rheumatoid arthritis tests.
There are many different blood tests used to diagnose and monitor rheumatoid arthritis. Some of these look for chemicals in the blood specifically associated with RA, while others measure overall immune system function or level of inflammation.
Rheumatoid factor is an antibody found in the blood of 70 to 80 percent of RA sufferers. Higher levels of rheumatoid factor correlate with more severe symptoms and faster progression of the disease. However, some people with RA test negative for rheumatoid factor, and some people without RA test positive, so it is not a 100 percent definitive test.
This is another antibody associated with RA. If you test positive for anti-CCP, there is about a 90 percent chance you have rheumatoid arthritis. A positive test for anti-CCP also indicates that RA is likely to progress more quickly. On the other hand, many RA patients test negative for anti-CCP, so this test is most often used in combination with other rheumatoid arthritis tests.
Anti-nuclear antibody (ANA) tests measure immune-system chemicals that indicate autoimmune disease. Thirty to 40 percent of RA patients test positive for anti-nuclear antibodies.
Erythrocyte Sedimentation Rate
Also called sed rate or ESR, this measures how quickly red blood cells separate out of the blood and settle to the bottom of a test tube. An elevated sed rate indicates a high level of inflammation in the body. The normal range for sed rate is under 22mm/hour for men and under 29 mm/hour for women.
This is a protein produced in the liver during episodes of severe inflammation or infection. C-reactive protein levels change more quickly than sed rate in response to changes in inflammation level, so this test is used to measure the effectiveness of medications at controlling RA.
X-rays use a specific type of radiation to take a picture of the inside of the body. X-rays of joints affected by RA are used to gauge the level of damage to cartilage, tendons, and bones to help determine the best method of treatment. A series of X-rays taken over a period of weeks or months can help doctors determine how quickly RA is progressing. However, X-rays are not helpful in detecting the presence of early RA because soft tissue will not show up on X-ray images.
Magnetic Resonance Imaging (MRI)
MRI uses a powerful magnetic field to take a picture of the inside of the body. Compared to X-rays, MRIs are better able to create images of soft tissue like muscles, organs, and blood vessels. MRIs allow doctors to look at the synovia (the membranes surrounding joints that are the immune system's target in RA), and can detect inflammation due to RA earlier than an X-ray can.