What does a rheumatoid factor of 415 mean?

Answer 1

A rheumatoid factor test measures the amount of rheumatoid factor in your blood. Rheumatoid factors are proteins produced by your immune system that can attack healthy tissue in your body.

High levels of rheumatoid factor in the blood are most often associated with autoimmune diseases, such as rheumatoid Arthritis and Sjogren's syndrome. But rheumatoid factor may be detected in some healthy people, and people with autoimmune diseases sometimes have normal levels of rheumatoid factor.

Results are usually reported in one of two ways:

• Less than 40-60 u/mL
• Less than 1:80 (1 to 80) titer

A low number (normal result) usually means you do not have rheumatoid arthritis or Sjogren syndrome. However, some people who do have these conditions still have a "normal" or low rheumatoid factor (RF).

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results MeanAn abnormal result means the test is positive, which means higher levels of rheumatoid factor have been detected in your blood.

• Most patients with rheumatoid arthritis or Sjogren syndrome have positive RF tests.
• The higher the level, the more likely one of these conditions is present. There are also other tests for these disorders that help make the diagnosis.
• Not everyone with higher levels of rheumatoid factor has rheumatoid arthritis or Sjogren syndrome.

Your provider may do another blood test (anti-CCP antibody) to help diagnose rheumatoid arthritis.

People with the following diseases may also have higher levels of rheumatoid factor:

• Scleroderma
• Systemic lupus erythematosus
• Adult Still's disease
• Dermatomyositis
• Sarcoidosis

Higher-than-normal levels of RF may be seen in people with other medical problems. However, these higher RF levels cannot be used to diagnose these other conditions: