Rheumatoid Factor
The Test Sample
What is being tested?
This test detects and measures rheumatoid factor (RF), a type of “autoantibody”, in the blood. We all have antibodies (also known as immunoglobulins) in our blood, which are protective proteins which defend the body against infection, particularly from bacteria. However, “autoantibodies” may attack the patient’s own tissues mistakenly identifying them as “foreign”. While the role of RF is not well understood, it may not directly cause joint damage, but promote the body's inflammation reaction which in turn contributes to autoimmune joint destruction.
The RF test is sensitive but not very specific, implying it can be found in diseases other than rheumatoid arthritis (RA). It is most closely associated with RA but may also be present in other autoimmune disorders, such as Sjögren’s syndrome, in some persistent bacterial and viral infections, and can be found in a small percentage of healthy people particularly in the elderly.
How is the sample collected for testing?
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
