Patients are clearly diagnosed with rheumatoid arthritis if they score 6 or more points according to the following criteria I. Joints involved 1. 1 medium to large joint (0 points); 2. 2-10 medium to large joints (1 point); 3. 1-3 small joints (2 points); 4. 4-10 small joints (3 points); 5. More than 10 small joints (5 points). II. Serology 1. Negative for rheumatoid factor and anti-citrullinated synthetic protein antibodies (0 points); 2. At least one of the two tests is positive for low titer. Low titer is defined as above the upper limit of normal but not higher than 3 times the upper limit of normal (2 points); 3. At least one test is positive for high titer, if the titer exceeds 3 times the upper limit of normal (3 points); 4. Domain: duration of synovitis (1) less than 6 weeks (0 points); (2) 6 weeks or longer (1 point). C. Acute phase reactants 1. normal C -reactive protein and erythrocyte sedimentation rate (0 points); 2. abnormal C -reactive protein or ESR (1 point). Within each domain, the highest score for which the patient is eligible is taken. If the patient has 5 small joints and 4 large joints involved, the score is 3.