Doctors measure the level of rheumatoid factor by performing a blood test. A positive rheumatoid factor test means that the level of rheumatoid factor in the patient’s blood is considered to be high.

Jan 18, 2024 · A normal, healthy amount of rheumatoid factor is less than 20 units per milliliter (<20 U/mL). Your provider might also refer to your test as being negative or positive.

Aug 26, 2023 · A positive rheumatoid factor test result shows that you have a high level of rheumatoid factor in your blood. A higher level of rheumatoid factor in your blood is closely linked with …

Aug 20, 2025 · Rheumatoid factor is an immune system protein. Its levels in the body can help doctors diagnose autoimmune conditions. Learn about tests and ranges here.

May 4, 2025 · The normal range of rheumatoid factor in blood is usually below 15 international units per milliliter or a titer of 1 to 80. The normal range may vary slightly depending on different...

A titer is a measure of how much the blood sample can be diluted before RF can no longer be detected. A titer of 1 to 20 (1:20) means that RF can be detected when 1 part of the blood sample is diluted by …

Rheumatoid factor is a blood test that helps to diagnose rheumatoid arthritis, lupus, and sarcoidosis. Elevated test results, or high levels, indicate severe disease. Learn about the normal range for …

Oct 16, 2025 · Antibodies directed against the Fc fragment of immunoglobulin G (IgG) are called rheumatoid factors (RFs). They are heterogenous and usually composed of immunoglobulin M (IgM).

Apr 1, 2025 · Results are usually reported in one of two ways: If the result is above the normal level, it is positive. A low number (negative result) most often means you do not have rheumatoid arthritis or …

Oct 25, 2023 · This is a single-marker test measuring rheumatoid factor. It is used for the diagnosis of rheumatoid arthritis and in monitoring the therapeutic response to the disease.