Patients with joint pain who go to the hospital often have tests for rheumatoid factor. The results may be reported as negative, positive or specific test data. However, many people have misconceptions about how to view these results. Does a positive rheumatoid factor mean that you have rheumatoid arthritis, but a negative test means that you do not have rheumatoid arthritis? Not necessarily! Rheumatoid factor is one of the many autoantibodies in the body and can be used as a basis for the diagnosis of rheumatoid arthritis. However, it is not a golden indicator for the diagnosis of rheumatoid arthritis. In patients with rheumatoid arthritis, 20-30% of rheumatoid factors are negative; at the same time, the rate of positive rheumatoid factors in the healthy population is 3-5%. Therefore, the rheumatoid factor cannot be used to determine whether a person has rheumatoid arthritis. According to the current diagnostic criteria, rheumatoid arthritis can be diagnosed if four or more of the following criteria are met: 1. Morning stiffness for 1 hour daily for 6 weeks or more. 2. Symmetrical joint swelling lasting for 6 weeks or more. 3. Swelling in at least one of the wrist, metacarpophalangeal and proximal interphalangeal joints, lasting for 6 weeks or more. 4.Swelling in three or more joint areas lasting for 6 weeks or more. 5.Rheumatoid nodules. 6.Positive rheumatoid factor. 7.Rheumatoid-like changes on imaging examination (taking a film). The results of rheumatoid factor have the following significance: 1. Positive rheumatoid factor can be used as one of the diagnostic bases to help diagnosis. If the test data is more than 5 times the upper limit of the normal value, it suggests a poor prognosis. 2, rheumatoid factor negative can not exclude rheumatoid arthritis. Combine with other diagnostic indicators for comprehensive consideration. Rheumatoid factor can also appear in systemic lupus erythematosus, scleroderma, dry syndrome, influenza, hepatitis, syphilis, tuberculosis, schistosomiasis, chronic liver disease and other diseases.