rheumatoid factor
noun
: an autoantibody of high molecular weight that reacts against IgG immunoglobulins and is often present in rheumatoid arthritis
Examples of rheumatoid factor in a Sentence
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These include tests that look for rheumatoid factor, anti-CCP antibodies, and the HLA-B27 gene.5
Imaging: Your healthcare provider may want an X-ray, magnetic resonance imaging (MRI) scan, or ultrasound of your affected joints.
—
Mark Gurarie, Health, 27 June 2025
It is classified into two subtypes: rheumatoid factor positive (RF) and rheumatoid factor negative.3 RF is an antibody that contributes to long-term inflammation.
—Lana Barhum, Verywell Health, 26 Sep. 2024
One of these blood tests measures the amount of rheumatoid factor (RF), a protein produced by your immune system that can attack healthy tissue, in your body.
—Women's Health, 4 Apr. 2023
Nearly everyone who is evaluated for psoriatic arthritis will have their blood tested for rheumatoid factor (RF), a protein produced by the immune system that attacks healthy joints.
—Sara Gaynes Lev, SELF, 30 July 2021
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Mark Gurarie, Health, 27 June 2025
It is classified into two subtypes: rheumatoid factor positive (RF) and rheumatoid factor negative.3 RF is an antibody that contributes to long-term inflammation.
—Lana Barhum, Verywell Health, 26 Sep. 2024
One of these blood tests measures the amount of rheumatoid factor (RF), a protein produced by your immune system that can attack healthy tissue, in your body.
—Women's Health, 4 Apr. 2023
Nearly everyone who is evaluated for psoriatic arthritis will have their blood tested for rheumatoid factor (RF), a protein produced by the immune system that attacks healthy joints.
—Sara Gaynes Lev, SELF, 30 July 2021
Cite this Entry
“Rheumatoid factor.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rheumatoid%20factor. Accessed 17 Sep. 2025.
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