What is RA test?

What is a rheumatoid factor (RF) test?

The rheumatoid factor (RF) test looks for rheumatoid factor (RF) in a blood sample. Rheumatoid factor is a protein produced by the immune system.

Your immune system makes proteins called antibodies to attack germs that can normally make you sick. However, rheumatoid factor is an antibody that sometimes mistakenly attacks the body's healthy cells and tissues.

When this happens, you have an autoimmune disease.

Not everyone has rheumatoid factor in their blood. And some people who have them are healthy. However, if you have certain symptoms and higher levels or rheumatoid factor, you may have an autoimmune disease or other health problem associated with high RF levels.

The

RF test is primarily used in conjunction with other tests to diagnose rheumatoid arthritis.

Rheumatoid arthritis (RA) is a type of autoimmune disease that damages joints and causes pain, swelling, and stiffness. It is a chronic (long-term) condition that can affect organs and cause other symptoms.

High levels of rheumatoid factor can also be a sign of other autoimmune diseases, some infections, and some types of cancer.

Other Name: RF Blood Test

What is it used for?

The RF test is often used to diagnose rheumatoid arthritis and other autoimmune diseases.

RF testing can also be used to understand how severe your rheumatoid arthritis is and whether it can affect your organs. RF testing by itself cannot diagnose a health problem.

Why is RF testing needed?

If you have rheumatoid arthritis symptoms, you may need an RF test. Symptoms often start in the wrists, hands, and feet.

They usually affect the same joints on both sides of the body and tend to come and go.

Symptoms of rheumatoid arthritis may include:

• Joint pain

• Tenderness, swelling, and warmth of the joint

• Joint stiffness that lasts longer than 30 minutes

• Fatigue

• Occasional low fevers

• Loss of appetite

• Problems outside of the joints that may include dry eyes or mouth, firm lumps under the skin, or anemia

What do the results mean?

An RF test alone cannot diagnose any conditions. To make a diagnosis, your provider will look at the results of other tests along with your symptoms and medical history.

A negative (normal) result means that you have little or no rheumatoid factor in your blood.

However, that does not rule out rheumatoid arthritis or other health problems. Many people with rheumatoid arthritis have little or no rheumatoid factor. If you have rheumatoid arthritis symptoms but your RF test results are normal, your doctor may order additional tests to make a diagnosis.

A positive (abnormal) result means a higher level of rheumatoid factor was detected in the blood. This does not always mean that the symptoms are caused by rheumatoid factor.

However, the higher the RF test result, the higher the chance that a person has a rheumatoid factor-related disorder. Your doctor may do more tests to find out if you have a disease, such as:

• Rheumatoid arthritis or other autoimmune diseases

• Chronic infections

• Certain types of cancer

Anything else I should know about the RF test?

Radiofrequency testing is not used to diagnose osteoarthritis. Although rheumatoid arthritis and osteoarthritis both affect joints, they are very different conditions. Osteoarthritis is not an autoimmune disease and is not related to rheumatoid factor.

Researchers aren't sure what causes osteoarthritis. It mainly affects the elderly.