Rheumatoid arthritis (RA) is an autoimmune disease caused by the body's own cells attacking the cells that line the joints, known as the synovial cells. Patients suffering from RA experience inflammation of the joints causing stiffness and pain that can be debilitating. Because these symptoms of RA are similar to other diseases, doctors perform a variety of tests to help them diagnose the disease as well as track its progression.
Blood Tests
Several different tests can be performed on blood taken from patients. A rheumatoid factor test determines the level of a specific antibody, a protein made by the immune system, call rheumatoid factor. The National Institutes of Health indicates that 80 percent of patients with RA test positive for rheumatoid factor; but since some patients with positive results will not have RA, it is not a definitive test.
An erythrocyte sedimentation rate (ESR) test is another blood test helpful in determining rheumatoid arthritis and its severity. The ESR measures the body's inflammatory response. The faster red blood cells fall to the bottom of a test tube, the higher the inflammatory response; therefore, the more likely to have RA.
A C-reactive protein test also determines the amount of inflammation in the body. Although it does not specifically diagnose RA, it is helpful when used with other diagnostic tests.
X-rays
X-rays, one of the oldest and most commonly used diagnostic tests, can provide useful information when testing for rheumatoid arthritis. Because x-rays cannot visualize the soft tissue, they are most useful in the later stages of the disease when bone erosion or joint space narrowing has occurred.
Magnetic Resonance Imaging
MRI, or magnetic resonance imaging, allows doctors to see the bone and soft tissue in and around the area in question. An MRI can help doctors to measure the volume of synovial fluid, the fluid in the joints. Doctors utilize MRI to measure the amount of inflammation in the joints to follow the progression of the disease and to determine the response to various types of treatment.
Symptom Questionnaire
The American Rheumatism Association created a patient questionnaire as a tool for doctors to utilize in a physical examination. This tool helps doctors to provide a differential diagnosis, as the symptoms of rheumatoid arthritis can be similar to those of other diseases. The questionnaire includes a list of seven symptoms. The patient must have been experiencing at least four of them for no less than two weeks for RA to be diagnosed. Lab Tests Online lists the symptoms included as morning stiffness, arthritis in at least three joint areas, arthritis in hand joints, symmetric (meaning occurring on both sides of the body) arthritis, the presence of rheumatoid nodules, positive for rheumatoid factor, and radiographic changes of the joints.
