A rheumatoid factor test is often ordered by a primary care physician before a patient is referred for specialist care or your rheumatologist may order the test to help pinpoint a diagnosis. The results, whether negative or positive, can provide useful information when trying to find the source of your symptoms.
What are rheumatoid factors (RF)? They are proteins produced by the body when the immune system is overactive and attacks healthy tissues in the body instead of only fighting germs and diseases. A rheumatoid factor test measures the level of RF in the blood.
Why This Test Is Done
A rheumatoid factor test is most often done to help diagnose rheumatoid arthritis and other autoimmune diseases that cause the body to attack itself. Your doctor may order other, related lab tests that can also provide valuable information diagnosing your symptoms.
Anti-nuclear antibody (ANA) and anti-cyclic citrullinated peptides (anti-CCP) tests show the levels of other “auto-antibodies” in your system. Auto-antibodies are those that attack healthy tissues.
To get a better idea of how much inflammation is present throughout the body, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) blood tests may be ordered as well.
What Your Results Mean
The normal range of RF in a rheumatoid factor test is typically between 10 and 20 IU/mL. The actual result can mean many things whether it falls within the normal range, it is slightly above normal, or very high. It can give your doctor a good indication of where to start looking for the right diagnosis. It’s possible that those with an autoimmune disease have a completely normal RF level and there are people without an autoimmune disease that may have a positive rheumatoid factor test.
Depending on the type of illness that is causing the high levels of RF, the immune system could be targeting your joints, organs within the body, or in the case of systemic lupus, the whole body. There are other conditions, however, that can cause a positive rheumatoid factor test, including some cancers and chronic infections.
It’s important to find the underlying cause of the positive rheumatoid factor test so it can be treated correctly, relieving your symptoms as much as possible and also slowing down or preventing any further damage. If you are experiencing symptoms, let us help you find a solution. Call Rheumatology Care of North Houston today at (832) 532-9779 to make an appointment.