What is it?
Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes stiffness, pain, loss of mobility, inflammation, and erosion (deterioration) in the joints. It usually affects multiple joints symmetrically, the hand and wrists most commonly, but also elbows, neck, shoulders, hips, knees, and feet. Other symptoms include fatigue, fever, the development of nodules under the skin, especially at the elbows, and a sense of not feeling well (malaise). Patients with RA may develop anemia, systemic complications, and may have other co-existing autoimmune disorders and symptoms such as the dry eyes and mouth associated with Sjögren’s syndrome.
Rheumatoid arthritis can affect anyone at any age, but it usually develops between the ages of 30 and 50. More than 75% of those affected are women. According to the National Institutes of Health, more than 2 million people in the United States have RA. Left untreated, RA can shorten a person’s lifespan and can, within a few years, leave about 30 to 40% of those affected too disabled to work. The course of RA and its prognosis are variable. It may develop and progress slowly or rapidly. It may go into remission in some patients and in a few it may go away. Pregnant women with RA frequently have decreased symptoms during their pregnancy and worsened symptoms after birth.
RA is different from osteoarthritis, in which joint tissue wears down from sports or injuries. RA usually affects joints in a balanced way—if one knee is affected, the other knee also is affected. The disease may be partly inherited through genes, but other factors are probably at work, including some kind of a trigger for the gene, perhaps bacteria or viruses. The disease is not contagious, however. Some scientists also think that changes in certain hormones may promote RA in people with certain genes who have been exposed to the triggering agent.
Testing
The goals with testing are to help diagnose rheumatoid arthritis, to distinguish it from other forms of arthritis and conditions with similar symptoms, and to evaluate its severity. Testing can be used to monitor the condition, its potential complications, response to treatment, and to monitor for potential side effects associated with some treatments.
There is no single test that can be used to diagnose rheumatoid arthritis; it is a diagnosis that is made through clinical evaluation with the assistance of laboratory and non-laboratory testing.
Laboratory Tests
Rheumatoid factor - used to help diagnose RA. It is eventually present in significant concentrations in about 80% of patients with RA but also present in other conditions and in a small percentage of healthy people.
Erythrocyte sedimentation rate – this test (sed rate or ESR) shows the presence of inflammation in the body and the activity of the disease
Cyclic Citrullinated Peptide Antibody (CCP) - a relatively new test that may be used to help diagnose RA, especially early in the disease and in patients who are RF negative.
Erythrocyte sedimentation rate (ESR) - this test shows the presence of inflammation in the body and the activity of the disease. It is used to help diagnose RA and to evaluate and monitor the condition. ESR will be increased in RA but not in osteoarthritis.
C-reactive protein test (CRP) - this test also indicates inflammation and tests for the activity of the disease. It may be used to help diagnose RA and to evaluate and monitor the condition. An increased level of CRP occurs in RA but not in osteoarthritis.
Complete Blood Count (CBC) – this is a group of tests that are used to help evaluate the patient’s red and white blood cells and hemoglobin to help evaluate and monitor the condition and complications such as anemia and/or a decreased white blood cell count.
Comprehensive Metabolic Panel (CMP) – this is a group of tests that may be used to help evaluate and monitor the patient’s kidney and liver function.
Non-Laboratory Tests
American Rheumatism Association criteria, including: morning stiffness, arthritis in at least 3 joint areas, arthritis in hand joints, symmetric arthritis, rheumatoid nodules, rheumatoid factor, and radiographic changes are used to help diagnose RA. (A diagnosis of RA is considered in a person who has had at least four of these criteria for several weeks).
X-ray – used to help diagnose RA and monitor joint damage but will not usually show significant changes early in the disease.
Ultrasound and MRI – being used primarily as research tools to attempt to detect changes in the joints earlier in the disease.
Source: Lab Test Online