A high rheumatoid factor is not necessarily rheumatoid. 1. Rheumatoid factor can be found in the normal population, and about 5% of people can be found to have increased rheumatoid factor during physical examination. 2. Elevated rheumatoid factor can also be found in patients with certain infectious diseases such as infective endocarditis and infectious mononucleosis. 3. Rheumatoid factor may also be increased in patients with autoimmune diseases such as systemic lupus erythematosus, dermatomyositis, dry syndrome, and vasculitis. 4. Some patients with rheumatoid arthritis may have high levels of rheumatoid factor. However, the diagnosis of rheumatoid arthritis, in addition to high rheumatoid factor, should also have at the same time, such as symmetric small joint arthritis, morning stiffness of the joints, subcutaneous rheumatoid nodules, anti-CCP antibody positive. High rheumatoid factor is not necessarily rheumatoid, such as patients with elevated levels of rheumatoid factor found in the laboratory, should be timely consultation, improve the relevant tests to clarify the diagnosis, under the guidance of the doctor’s treatment.