Currently, the more widely used international diagnostic criteria are those established by the American College of Rheumatology in 1987 for the diagnosis of rheumatoid arthritis: 1. Morning stiffness lasting at least 1 hour (per day) for at least 6 weeks 2. Swelling of 3 or more joints for at least 6 weeks 3. Swelling of the wrist, metacarpophalangeal, and proximal phalangeal joints for at least 6 weeks 4. Symmetrical joint swelling for at least 6 weeks 5. Subcutaneous nodules 6. Radiographic changes of the hand (at least osteoporosis and narrowing of the joint space) 7. Elevated levels of serum rheumatoid factor (rheumatoid factor is an autoantibody in the body that can be used to diagnose rheumatoid arthritis). Four of the above seven items can be diagnosed as rheumatoid arthritis. For patients with suspected rheumatoid arthritis, it is necessary to master the diagnostic criteria for rheumatoid arthritis and strive for early diagnosis.