The RF factor is an antibody found in about 80% of people with RA but can also be found in people who do not have the disease. The RF factor is not used to exclusively diagnose RA as is it also found in Sjogren's Syndrome, Lupus, or other infections. High levels of rheumatoid factor are associated with a tendency toward more severe rheumatoid disease. This factor is also associated with a higher tendency to develop non-joint manifestations of rheumatoid disease, such as rheumatoid nodules and rheumatoid lung disease. 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). Your doctor will use this number to help diagnose your disease but will take into consideration what your symptoms are, joints inflamed, pain, fatigue etc. A high CCP is a used to diagnose RA also. Trying to diagnose an autoimmune disease is not easy. If you go to the doctor with pneumonia, it is a very clear diagnosis and protocol they will use. No so with the autoimmune diseases. The are like a jigsaw puzzle. I hope this makes a little more sense to you, :)