Rheumatoid Factor (RA Factor) - Quantitative – BC272
🦴 Autoimmune Arthritis TestReport: Same Day
Sample Type: Blood (Serum)
Test Code: BC272
The Rheumatoid Factor (RA Factor) - Quantitative test is a blood test that detects and measures the exact amount of Rheumatoid Factor, an autoantibody present in the blood of many people with Rheumatoid Arthritis and other autoimmune diseases.
✔ A key blood test in the diagnostic workup for Rheumatoid Arthritis (RA).
✔ A quantitative result provides the exact level (titer), which can help assess disease severity.
✔ Higher levels are often associated with more severe joint disease.
✔ A simple blood test with same-day reporting.
What is Rheumatoid Factor (RF)?
Rheumatoid Factor is an autoantibody, meaning it's an antibody produced by the immune system that mistakenly targets the body's own tissues. Specifically, RF targets the "Fc" portion of Immunoglobulin G (IgG), another type of normal antibody. This interaction forms immune complexes that can deposit in the joints and other tissues, triggering inflammation and causing damage.
While the presence of RF is a hallmark of Rheumatoid Arthritis (found in about 70-80% of RA patients), it is not exclusive to it. It can also be found in other autoimmune conditions like Sjögren's syndrome and Lupus, in chronic infections, and even in a small percentage of healthy individuals, especially the elderly.
The Value of a Quantitative Test
This test provides a quantitative result, meaning it gives an exact concentration or "titer" (e.g., in IU/mL) rather than just a positive or negative result. This is clinically important:
- Diagnostic Clue: While a positive result of any level is significant, a very high titer of RF is more strongly specific for Rheumatoid Arthritis.
- Prognostic Information: In patients diagnosed with RA, a high RF titer is often associated with a more aggressive or severe form of the disease, with a higher likelihood of joint damage and extra-articular (outside the joints) manifestations.
Because RF is not 100% specific for RA, doctors will always interpret this result in conjunction with your clinical symptoms (like joint pain and swelling) and other more specific blood tests, such as the Anti-CCP antibody test.
Frequently Asked Questions (FAQ)
Your doctor likely ordered this test because you are experiencing symptoms like persistent joint pain, stiffness, and swelling, which are suggestive of an inflammatory arthritis like Rheumatoid Arthritis (RA).
Not necessarily. While RF is found in most people with RA, it can also be positive in other autoimmune diseases, chronic infections, and even in some healthy people. Your doctor will use this result as one piece of a larger diagnostic puzzle.
Yes. About 20-30% of people with Rheumatoid Arthritis are "seronegative," meaning their RF test is negative. In these cases, diagnosis relies more heavily on clinical symptoms and other tests like Anti-CCP.
A quantitative result measures the exact amount of RF in your blood. A very high level is more strongly suggestive of RA and may indicate a more severe form of the disease, which can help your doctor plan your treatment.
No, fasting is not required for the Rheumatoid Factor blood test.