Rheumatoid Arthritis

Alternate Names : RA

How is the disease diagnosed?

Observing the person and his or her pattern of symptoms, along with a medical history and physical exam, helps the doctor to diagnose RA. A blood test for the rheumatoid factor is positive in about 80% of cases but does not mean the person has RA.

Other blood tests, such as a complete blood count, called CBC; C4 complement components; C-reactive proteins, called CRP; and antinuclear antibody, called ANA; tests may be done. People with RA are often anemic and have a low number of red blood cells in their blood count. Joint aspiration, which means removing joint fluid with a needle under local anesthesia, might be done. Synovial fluid that is cloudy, milky, or dark yellow and that contains many inflammatory cells will help detect RA.

Joint X-rays may also be ordered to help diagnose RA. It is important to rule out other diseases and conditions, such as other types of arthritis, as well as condition such as systemic lupus erythematosus and Lyme disease.