In clinical practice, we often encounter patients who ask: Is it possible that I have rheumatoid arthritis if I am found to be positive for rheumatoid factor during physical examination? What should I do? What should be done for these patients? The following is an explanation. In fact, the rheumatoid factor we routinely test in hospitals is IgM type. The rheumatoid factor positive can be seen in a variety of diseases, the highest positive rate in patients with rheumatoid arthritis, up to 80%, such as rheumatoid nodules and splenomegaly, the positive rate of about 85%, serious cases can exceed 90%, is one of the serological indicators for the diagnosis of rheumatoid arthritis. The diagnostic value of rheumatoid factor for rheumatoid arthritis increases with the following factors: ① high titer: persistent high titer IgM rheumatoid factor can indicate disease activity, bone erosion and poor prognosis; ② more than 2 consecutive positive tests; ③ positive by multiple methods; ④ reactive with both human and animal IgG molecules; ⑤ in addition to IgM rheumatoid factor, there are also IgG, IgA or IgE rheumatoid factors. In addition to IgM rheumatoid factor, there are also IgG, IgA or IgE rheumatoid factors. The rate of rheumatoid factor positivity is about 1% to 3% in healthy adults, 5% in older adults, 0.3% in infants, 10% to 20% in children, and increases by a factor of 1 for every 10 years of age in the elderly, and up to 25% in those older than 75 years. In other words, a patient with a positive rheumatoid factor does not necessarily have rheumatoid arthritis, and conversely, a negative rheumatoid factor does not necessarily not have rheumatoid arthritis. The diagnosis of rheumatoid arthritis should be made by combining symptoms, signs, laboratory tests and imaging examinations. If the rheumatoid factor is positive, the titer should be further checked and serological indicators used for the early diagnosis of rheumatoid arthritis, such as antiperinuclear factor, anti-keratin antibodies, anti-cyclic citrullinated peptide antibodies, and autoantibodies used for the diagnosis of other autoimmune connective tissue diseases, such as anti-nuclear and anti-ENA antibodies, should be measured. In summary, if the test is positive for rheumatoid factor, it is still necessary to conduct a rational analysis and not to use drugs blindly.