1, RF negative: rheumatoid factor positive is an important basis for the diagnosis of rheumatoid arthritis, but some normal people can also appear rheumatoid factor positive, known as laboratory-induced false positive, in addition to many other diseases can also appear rheumatoid factor positive, such as dry syndrome, systemic lupus erythematosus, various liver diseases, chronic bronchitis, emphysema, syphilis, dermatomyositis, etc. Therefore, a positive rheumatoid factor does not necessarily mean rheumatoid arthritis. Therefore, the diagnosis of rheumatoid arthritis should be a comprehensive judgment. In addition, rheumatoid factor titer can also respond to rheumatoid activity, the normal value of 1:20, greater than it is positive, the greater the ratio, the higher the activity. 2, the joint does not hurt, rheumatoid arthritis is well? It’s not that simple. Currently developed the criteria for determining the clinical remission of rheumatoid arthritis. (1) Morning stiffness does not exceed 15 minutes. (2) No weakness. (3) No joint pain. (4) No joint tenderness or pain on movement. (5) No soft tissue swelling in the joint area and tendon sheath. (6) Erythrocyte sedimentation rate (Weil’s method) less than 2 cm/hour (female) or less than 1.5 cm/hour (male). Patients with rheumatoid arthritis meet at least 5 of the above criteria and last for 2 months without any treatment to be judged in clinical remission. 3, children buttock pain (spondyloarthropathy): children or adolescents buttock pain, when pay sufficient attention to the early manifestations of spondyloarthropathy in part.