Summary

• Rheumatoid factors are autoantibodies.
• Your immune system makes antibodies to fight off harmful things, including infections.
• Autoantibodies are the name given to antibodies that are made when your immune system attacks your own healthy tissues by mistake. When this happens, it is called an autoimmune disorder.
• Testing for RFs is mostly used to diagnose rheumatoid arthritis (RA) and Sjögren’s syndrome.
• Less often, RF levels can also be high due to other autoimmune conditions, infections or cancer.
• Almost everyone with RA and most with Sjögren’s syndrome have RFs in their blood although it can take years for them to appear.

What is RF (Rheumatoid factor)?

Rheumatoid factors are autoantibodies. Your immune system fights harmful things including bacteria and viruses by making antibodies. If you have an autoimmune disorder, your immune system is making antibodies that mistakenly attack your own body. These are called autoantibodies.

Autoimmune disorders have a systemic effect on the body and are very complex. Diagnosing them is challenging and can take time, as symptoms can take months or years to develop. There are many types of autoimmune disorders, and each type affects your body in different ways.

Although high levels of certain autoantibodies are linked to specific autoimmune disorders, they can also be often found in healthy people.

Pathology tests are needed to make a diagnosis and many blood tests can be involved. Some tests look for levels of inflammation, others detect the autoantibodies your body makes, while others look for certain health conditions that are associated with specific disorders.

No single test can give a definite diagnosis. Multiple test results, along with your clinical symptoms, medical history, and imaging tests, are needed to make a diagnosis.

Why get tested?

The RF test is mostly used alongside other tests, to help diagnose rheumatoid arthritis (RA) and an arthritis-related condition called Sjögren’s syndrome. About 80 to 90 per cent of people with Sjögren’s syndrome have high levels of RF in their blood although it can take years to appear.

Other conditions, such as Raynaud’s syndrome, scleroderma, autoimmune thyroid disorders, and systemic lupus erythematosus (SLE) are also common among people with Sjögren's syndrome.

Having the test

Sample

Blood

Preparation

None

Your results

Reading your test report

Your results will be presented along with those of your other tests on the same form. You will see separate columns or lines for each of these tests.

Negative (normal) result means that you have little or no RF in your blood sample. This may mean that you do not have an autoimmune condition, or it is too early in your disease progression to detect RF. Many people with RA have little or no RF.

If you have a negative RF test result, but your symptoms appear to be those of RA or Sjögren’s syndrome, the RF test may need to be done again. Autoimmune disorders can take time to show up and tests may need to be repeated over several months to make a diagnosis. This can help rule out other possible causes of your symptoms.

Positive (abnormal) result means that higher levels of RF were found in your blood. The higher the levels of RF, the more likely they are causing your symptoms. However, high levels of RF may also be linked to other conditions, including endocarditis, SLE tuberculosis, syphilis, sarcoidosis, cancer, viral infection, or disease of the liver, lungs or kidneys.

Another test that may be needed to diagnose RA is anti-cyclic citrullinated peptide (CCP) antibody testing.

Questions to ask your doctor

The choice of tests your doctor makes will be based on your medical history and symptoms. It is important that you tell them everything you think might help.

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.

Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results.

Ask:

• Why does this test need to be done?
• Do I need to prepare (such as fast or avoid medications) for the sample collection?
• Will an abnormal result mean I need further tests?
• How will the results from this test change the course of my care?
• What will happen next, after the test?

More information

Pathology and diagnostic imaging reports can be added to your My Health Record. You and your healthcare provider can now access your results whenever and wherever needed.

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