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
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.