Description: Rheumatoid Factor IgG is a blood test that measures the amount of rheumatoid factor IgG antibodies that are present in the blood’s serum.
Also Known As: RF Antibody Test, Rheumatoid Arthritis Factor Antibody Test, RF IgG Test, RF IgG Antibody Test, Rheumatoid Factor IgG Antibody Test
Collection Method: Blood Draws
Specimen Type: Serum
Test Preparation: No preparation required
When is a Rheumatoid Factor IgG test ordered?
When a person has RA signs and symptoms, an RF test may be ordered. Pain, warmth, swelling, and morning stiffness in the joints are common symptoms, as are nodules under the skin and, if the disease has progressed, signs of enlarged joint capsules and cartilage and bone loss on X-rays. When the first RF test is negative but the symptoms persist, the RF test may be repeated.
A cyclic citrullinated peptide antibody test may be ordered along with RF or if the RF result is negative to help diagnose RA in someone who has joint inflammation but does not yet fit the criteria for RA.
Additional autoimmune-related tests, such as an ANA, as well as other markers of inflammation, such as a CRP and Sed Rate, as well as a CBC to examine blood cells, may be ordered in addition to the RF test.
What does a Rheumatoid Factor IgG blood test check for?
The autoantibody rheumatoid factor is an immunoglobulin M protein produced by the body's immune system. Autoantibodies attack a person's own tissues, mistaking them for "foreign" tissue. While the biological role of RF is unknown, its presence can be used to detect inflammatory and autoimmune activities. This test identifies and quantifies radiofrequency in the bloodstream.
The RF test is an important tool in the diagnosis of rheumatoid arthritis. A RF test will be positive in about 80% of people with RA. RF, on the other hand, can be found in persons with a range of different illnesses, including as Sjögren syndrome, as well as persistent bacterial, viral, and parasite infections, and some malignancies. It can be noticed in patients who have lung, liver, or kidney disease, and it can also be detected in a tiny percentage of healthy persons.
Lab tests often ordered with a Rheumatoid Factor IgG test:
- Rheumatoid Factor IgM
- Cyclic Citrullinated Peptide Antibody
- Sed Rate
- C-Reactive Protein
Conditions where a Rheumatoid Factor IgG test is recommended:
- Rheumatoid Arthritis
- Autoimmune Disorders
How does my health care provider use a Rheumatoid Factor IgG test?
The rheumatoid factor test is used to diagnose rheumatoid arthritis and to distinguish it from other types of arthritis or diseases that generate similar symptoms.
While the clinical picture is critical in the diagnosis of RA, some signs and symptoms, particularly in the early stages of the disease, may not be present or follow a predictable pattern. Additionally, the signs and symptoms may not always be easy to distinguish because people with RA may also have other connective tissue disorders such Raynaud phenomenon, scleroderma, autoimmune thyroid problems, and systemic lupus erythematosus and present symptoms of these disorders. When RA is suspected, the RF test is one of several tools that can be used to aid determine a diagnosis.
What do my Rheumatoid Factor test results mean?
The results of the RF test must be interpreted in the context of a person's symptoms and medical history.
The presence of large amounts of RF in persons with symptoms and clinical indications of rheumatoid arthritis indicates that they are likely to develop RA. Higher RF levels are associated with a worse prognosis and more severe illness.
A negative RF test does not rule out the possibility of RA. Around 20% of persons with RA will have very low levels of RF or none at all. In these circumstances, a positive CCP antibody test can be utilized to confirm RA.
Sjögren syndrome, systemic lupus erythematosus, sarcoidosis tuberculosis, syphilis, HIV/AIDS, hepatitis, scleroderma, infectious mononucleosis, cancers such as leukemia and multiple myeloma, or disease of the liver, lung, or kidney may all produce positive RF test These other disorders are neither diagnosed or monitored with the RF test.
We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.