Rheumatoid Factor (RA), Quantitative
Rheumatoid factor (RF) is an antibody often elevated in rheumatoid arthritis and other autoimmune conditions. A positive result supports the diagnosis of RA but can also occur in other diseases and healthy elderly individuals.
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What the Rheumatoid Factor (RA), Quantitative test tells you
Rheumatoid factor is an antibody that the immune system directs against part of the body's own antibodies. It is most often of the IgM class, it circulates in the blood, and a quantitative test reports how much of it is present rather than a simple yes or no. The presence of such a self-directed antibody is one of the signs that the immune system is behaving in an autoimmune way, which is why the test appears so often in the assessment of joint disease.
In practice the result is only one input. A doctor assessing painful, swollen joints will weigh the pattern of the joints involved, how long stiffness lasts in the morning, imaging of the hands and feet, general markers of inflammation such as CRP and the sedimentation rate, and the more specific anti-CCP antibody. Higher rheumatoid factor levels tend to keep company with more aggressive joint disease and with features outside the joints, such as nodules or lung involvement, but the number itself does not grade the illness and does not track how active it is from month to month.
The important caution runs in both directions. A positive rheumatoid factor is common in people who do not have rheumatoid arthritis at all: it is found in healthy older adults, in Sjogren's syndrome and lupus, in chronic hepatitis C and other long-standing infections, and in some chronic liver and lung conditions. At the same time, a substantial proportion of people who genuinely have rheumatoid arthritis never test positive, a pattern doctors call seronegative disease. The test supports a diagnosis; it does not make one and it does not rule one out.
Part of the diagnostic workup for rheumatoid arthritis, especially alongside anti-CCP antibodies. Also useful in evaluating other autoimmune and infectious conditions.
- Supporting a rheumatology assessment
It adds one piece of laboratory evidence to the clinical picture when inflammatory joint disease is being considered. It is interpreted alongside examination, imaging and other antibodies.
- Investigating persistent joint pain
Where several small joints have been painful and swollen for weeks, the result helps a doctor decide how urgently to involve a rheumatologist.
- Flagging a more aggressive pattern
Higher levels are associated with disease that affects more than the joints. This can influence how closely someone is followed up.
- Assessing other autoimmune illness
The same antibody appears in conditions such as Sjogren's syndrome and in some chronic infections, so it can point towards a broader immune investigation.
Reasons your doctor may request the Rheumatoid Factor (RA), Quantitative test
Your doctor may order this test for any of the reasons below. Some are routine checks, others follow specific symptoms or an earlier result.
Joint pain & stiffness
- Pain, swelling and stiffness affecting the small joints of the hands, wrists or feet on both sides of the body.
- Morning stiffness that takes a long time to loosen rather than easing within a few minutes of moving.
- Dry eyes and a dry mouth occurring together with joint complaints.
Raised inflammatory markers
- Raised inflammatory markers alongside joint symptoms, with no infection to explain them.
Family history & specialist referral
- A family history of rheumatoid arthritis in someone developing early joint symptoms.
- Baseline assessment before a specialist review of suspected inflammatory arthritis.
A result in the Normal band, 0 to 14 IU/mL, is reported as negative and has no meaning of its own. It does not close the question of rheumatoid arthritis either, because a substantial proportion of people with the condition never test positive. A High result, 15 to 200 IU/mL, supports the possibility but is far from specific to it. Rheumatoid factor also turns up in Sjogren's syndrome, lupus and other connective tissue diseases, in chronic infections such as hepatitis C, infective endocarditis and tuberculosis, in chronic liver disease and conditions like sarcoidosis, and in healthy older adults with no autoimmune disease at all, so positive results become commoner with age. The level does not track day-to-day disease activity, so it is not used to follow treatment. Your doctor reads it with your examination, imaging, anti-CCP antibodies, your symptoms and your history.
Medically reviewed by Dr Nirupama Sabhapathy
Ranges are a guide: your physician interprets your result alongside your symptoms and history.
What a higher result can point to
- Rheumatoid arthritis, where the antibody is present in a majority but not all of those affected.
- Sjogren's syndrome, lupus and other connective tissue diseases.
- Chronic infections, in particular hepatitis C, infective endocarditis and tuberculosis.
- Chronic liver disease and some long-standing lung conditions such as sarcoidosis.
- Increasing age in people with no autoimmune disease at all.
- Cryoglobulinaemia and some lymphoid disorders.
These are possibilities, not diagnoses. A single value outside the reference range is interpreted alongside your symptoms, history and other tests: your doctor decides what it means for you.
What this test cannot tell you
- A positive result is common in people without rheumatoid arthritis, including healthy older adults and people with chronic hepatitis C, Sjogren's syndrome or other long-standing infections.
- A negative result does not exclude rheumatoid arthritis, because a substantial proportion of people with the condition never test positive.
- The level does not follow day-to-day disease activity, so it is not a useful way to monitor treatment response.
- A low or undetectable result has no meaning of its own and is not reported as an abnormality.
Risks of the blood draw
- Mild bruising or brief soreness where the needle went in.
- Occasional lightheadedness, which settles after a few minutes of rest.
- Bleeding or infection at the site, which is rare with sterile single-use equipment.
- 1Rheumatoid factor is an antibody aimed at the body's own antibodies, most often of the IgM class.
- 2It is one input to a diagnosis that rests on clinical assessment, imaging and other antibodies.
- 3Positive results occur in other autoimmune conditions, in chronic infections and in healthy older adults.
- 4Seronegative rheumatoid arthritis is real, so a negative result never closes the question.
- 5Anti-CCP antibodies are more specific for rheumatoid arthritis and are often requested with this test.
Rheumatoid Factor (RA), Quantitative also comes in these focused packages, which pair it with the tests usually read alongside it.
- Immunology / SerologyC-Reactive Protein (CRP)
CRP is a protein produced by the liver in response to inflammation. Elevated levels indicate an active inflammatory process, which could be caused by…
60View - HaematologyErythrocyte Sedimentation Rate (ESR)
ESR measures how quickly red blood cells settle in a tube over one hour. A faster rate suggests inflammation in the body from infections, autoimmune…
25View - HaematologyComplete Blood Count (CBC)
The CBC is the most commonly ordered blood test. It measures red blood cells, white blood cells, haemoglobin, haematocrit, and platelets to assess…
35View - BiochemistryUric Acid
Uric acid is a waste product from purine metabolism. Elevated levels can cause gout (painful joint inflammation) and kidney stones, and are…
25View
Frequently Asked Questions
Everything you need to know about the Rheumatoid Factor (RA), Quantitative test. Can't find what you're looking for?
Talk to our team→Our laboratory reports 0 to 14 IU/mL as normal, which is read as a negative result. A result of 15 to 200 IU/mL is reported as high and may support rheumatoid arthritis, but it is far from specific to it. Neither result settles the diagnosis alone: your doctor reads it with your joints, imaging and anti-CCP antibodies.
Besides rheumatoid arthritis, rheumatoid factor turns up in Sjogren's syndrome, lupus and other connective tissue diseases, in chronic infections such as hepatitis C, infective endocarditis and tuberculosis, in chronic liver disease, sarcoidosis, cryoglobulinaemia and some lymphoid disorders. It also becomes commoner with age in healthy people, so your doctor considers these before linking it to your joints.
Rheumatoid arthritis typically causes pain, swelling and stiffness in several joints, often the small joints of the hands and feet on both sides, with stiffness that is worst in the morning. Tiredness is common. A blood test cannot replace an examination, so persistent joint swelling should be assessed by a doctor whatever the rheumatoid factor result.
It can. Short-lived immune activity after a recent infection or a vaccination in the past few weeks can influence antibody tests, and chronic infections such as hepatitis C or tuberculosis can keep rheumatoid factor positive. Mention any of these, and any steroid, biologic or immune-suppressing treatment, so your doctor can interpret the result fairly.
No. The antibody is found in several other conditions and in a proportion of healthy older adults with no joint disease. Your doctor reads it together with your symptoms, examination, imaging and other blood tests before reaching any conclusion.
Yes. A meaningful number of people with rheumatoid arthritis never have detectable rheumatoid factor. This is described as seronegative disease, and it is diagnosed on the clinical picture, imaging and sometimes other antibodies instead.
Anti-CCP antibodies are far more specific to rheumatoid arthritis, so a positive anti-CCP points more firmly at that diagnosis. Rheumatoid factor is more widely positive across other illnesses. The two are often requested together because they answer slightly different questions.
Usually not for monitoring. The level does not reliably fall as symptoms improve, so doctors follow disease activity through your symptoms, joint examination and inflammatory markers rather than through repeat rheumatoid factor testing.
No fasting is needed and the sample can be given at any time of day. Take your usual medicines as prescribed, and tell the team about any steroid, biologic or immune-suppressing treatment you are on.
The rheumatoid factor test is AED 70, including a physician-reviewed report, with results usually within 24 hours. Home collection anywhere in Dubai is free when your order reaches AED 300 or includes a package; below that, a AED 100 home collection fee applies (AED 50 for a lab walk-in).