Rheumatoid Factor Panel in Arizona

What this test measures

Rheumatoid factor is an autoantibody, meaning it targets part of the person's own immune system rather than an outside invader. It is found in many people with rheumatoid arthritis, but it can also appear in other autoimmune conditions, chronic infections, and even in some healthy individuals. Because of this, the test contributes to a broader assessment rather than standing alone.

The test measures rheumatoid factor in a blood sample, most commonly the IgM class, and some laboratories also report IgA or IgG forms. Results are given as a quantitative level, often with a reference range or titer. A related test for anti-cyclic citrullinated peptide antibodies is frequently ordered at the same time because it is more specific for rheumatoid arthritis.

Clinicians may order this test when joint symptoms last several weeks, when several joints are involved, or when morning stiffness is prominent. It can also be used to monitor a known condition or to help distinguish between types of inflammatory arthritis. A qualified healthcare provider interprets the result with the examination, imaging, and other laboratory findings.