Can I have rheumatoid arthritis with a negative rheumatoid factor test?

Yes, approximately 15-30% of people with rheumatoid arthritis have negative RF tests, a condition called seronegative rheumatoid arthritis. Diagnosis in these cases relies on clinical symptoms, physical examination findings, imaging studies, and other laboratory tests such as anti-CCP antibodies.

How accurate is the rheumatoid factor test for diagnosing rheumatoid arthritis?

The RF test has moderate sensitivity and specificity for rheumatoid arthritis. While positive in about 70-80% of RA patients, it can also be elevated in other autoimmune conditions, chronic infections, and even in some healthy individuals. The test is most useful when combined with clinical evaluation and other diagnostic markers.

What other conditions can cause elevated rheumatoid factor levels?

Elevated RF levels can occur in Sjögren's syndrome, systemic lupus erythematosus, chronic infections like hepatitis C and tuberculosis, certain cancers, and sarcoidosis. Some healthy individuals, particularly older adults, may also have mildly elevated levels without any underlying disease.

Should I be concerned if my rheumatoid factor is slightly elevated but I feel fine?

Mildly elevated RF levels in the absence of symptoms are not necessarily concerning, as they can occur in healthy individuals. However, it's important to discuss results with a healthcare provider who can evaluate them in the context of your overall health, family history, and any subtle symptoms you might not have noticed.

How often should rheumatoid factor testing be repeated?

For monitoring diagnosed rheumatoid arthritis, RF levels typically remain stable and don't require frequent testing. However, your healthcare provider may recommend periodic testing if you're at risk for autoimmune conditions or if you develop new symptoms. Once positive, RF usually remains positive even during treatment remission.

Can medications or other factors affect rheumatoid factor levels?

Most common medications do not significantly affect RF levels. However, certain immunosuppressive treatments used for autoimmune conditions may influence results over time. Age can naturally increase RF levels slightly, and acute infections might temporarily affect results, though this is less common than with other inflammatory markers.

Autoimmune & Inflammation

Rheumatoid Factor (RF)

Measures rheumatoid factor antibodies in the blood to help diagnose rheumatoid arthritis and other autoimmune conditions.

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What this test measures

The Rheumatoid Factor (RF) test measures a class of antibodies that, rather than targeting bacteria or viruses, attack immunoglobulin G (IgG), one of the body's own protective proteins. RF antibodies are most commonly of the IgM type, though IgG and IgA forms also exist. Their presence indicates that the immune system is misdirecting some of its activity against the body's own tissues.

Small amounts of rheumatoid factor circulate in the blood of many healthy people without causing problems, but elevated levels are associated with autoimmune conditions, most notably rheumatoid arthritis. RF testing is most useful when combined with clinical symptoms, imaging, and other laboratory markers such as anti-CCP antibodies. The test helps healthcare providers evaluate inflammatory conditions affecting the joints and other body systems and contributes to a broader diagnostic picture of autoimmune activity.

Who should consider this test

You might consider this test if you are experiencing any of the following:

Individuals experiencing joint pain, stiffness, or swelling that persists for several weeks, particularly affecting multiple joints
Those with morning stiffness lasting more than one hour, which may indicate inflammatory arthritis conditions
Patients with a family history of rheumatoid arthritis or other autoimmune diseases, as genetic factors can increase risk
Individuals with unexplained fatigue, low-grade fever, or general feelings of illness accompanying joint symptoms
People seeking evaluation for suspected autoimmune conditions such as Sjögren's syndrome or systemic lupus erythematosus
Those with chronic infections or inflammatory conditions that may be associated with elevated rheumatoid factor levels

What to expect

Preparation

No special preparation is required for the rheumatoid factor test. No fasting is necessary, and medications typically do not need to be discontinued before testing. However, individuals should inform their healthcare provider about all medications and supplements they are taking.

Sample Type

A blood sample is collected from a vein, typically in the arm. The procedure involves inserting a small needle to draw blood into a collection tube.

Collection

The blood draw is performed by a trained phlebotomist or healthcare professional. The skin is cleaned with an antiseptic, and a needle is inserted into a vein to collect the sample. The process typically takes just a few minutes and may cause brief discomfort.

Turnaround

Results are typically available within 1-2 business days. Some laboratories may provide results on the same day, while others may take up to 3 business days depending on the specific testing method used.

Understanding your results

Results are typically reported as a numerical value in units per milliliter (U/mL), with levels below 20 U/mL generally considered normal. Higher levels tend to correlate more strongly with autoimmune conditions, particularly rheumatoid arthritis, though the relationship is not absolute. Both false positives (RF detected in people without autoimmune disease) and false negatives (RF absent in people who do have rheumatoid arthritis) can occur, which is why healthcare providers always interpret RF results alongside clinical symptoms, physical examination, and additional tests like anti-CCP and inflammatory markers.

Population	Reference Range	Notes
Adults (all ages)	Less than 14-20 IU/mL or U/mL	Normal range varies slightly between laboratories but is typically less than 20 U/mL. Values may be slightly higher in older adults.

Reference ranges shown are general guidelines. Your lab report will include the specific reference range used by the laboratory that processed your sample, which is the authoritative range for interpreting your results.

What does a “Low” result mean?

Low or undetectable rheumatoid factor levels typically indicate normal immune system function regarding this particular antibody. A negative (normal) result means that you have little or no rheumatoid factor in your blood. But that doesn't rule out rheumatoid arthritis or another health problem. About 20% of those with confirmed RA will not have an abnormal RF test, a condition known as seronegative rheumatoid arthritis. People with seronegative arthritis are typically at lower risk of severe disease progression and developing other complications. However, seronegative arthritis is still a serious condition that can require medical management and treatment.

What does a “High” result mean?

Elevated rheumatoid factor levels may indicate several conditions, with rheumatoid factor present in the serum of a majority of patients with rheumatoid arthritis and patients with rheumatoid arthritis who have high titer rheumatoid factor are more likely to have severe disease and systemic involvement than other patients. However, RF is also present with other connective tissue diseases, autoimmune disorders, and proinflammatory states. For example, RF is found in 52% and 98% of individuals with primary or secondary Sjögren's syndrome (an autoimmune disease), respectively. They are also frequently found to be elevated in some non-rheumatic diseases, especially chronic infections like hepatitis C, tuberculosis, and subacute infective endocarditis. Sarcoidosis and malignancies like primary sclerosing cholangitis also have RF elevation. RF is also observed in 1-5% of healthy individuals.

Privacy & confidentiality

All test orders are authorized and results reviewed by an independent, board-certified physician who is not the patient's personal doctor. Your rheumatoid factor test results are completely confidential and protected by strict medical privacy laws. The results are not reported to your doctor unless you specifically request that they be shared, and they are not part of your medical records unless you choose to add them. Your test results will not appear on insurance statements or explanation of benefits (EOB) forms, ensuring complete privacy from insurance companies and employers. This confidential testing allows individuals to understand their autoimmune status privately, which can be particularly important when exploring potential inflammatory conditions or monitoring health without affecting insurance coverage or employment opportunities. All results are securely delivered through your private online account, and no third parties have access to your information without your explicit consent.

Frequently asked questions

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Last reviewed: April 2026

CPT Code: 86431

This test may not be available in: NY, NJ, RI

This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.

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This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.

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