THE AMERICAN RHEUMATISM ASSOCIATION 1987 REVISED CRITERIA FOR THE CLASSIFICATION OF RHEUMATOID ARTHRITIS
1. Morning stiffness in and around joints and lasting at least 1 hour in duration before improvement.
2. Arthritis of 3 or more joint areas. Characterized by soft tissue swelling or fluid which should be observed and documented by a physician. The 14 possible areas of involvement are the right or left PIP, MCP, wrist, elbow, knee, ankle, and MTP joints.
3. Arthritis of the hand joints.
4. Symmetric arthritis. May be asymmetric at disease onset; however, as the disease becomes chronic, the symptoms progress into a symmetric pattern of distribution.
5. The presence of rheumatoid nodules. These are subcutaneous nodules located over bony prominences, or extensor surfaces, or in juxta-articular regions.
6. A positive serum rheumatoid factor titer.
7. The presence of characteristic changes typical of rheumatoid arthritis on radiographic examination. These changes must include erosions or unequivocal bony decalcification localized in or adjacent to the involved joints and noted on posteroanterior hand and wrist radiographs.
The diagnosis of rheumatoid arthritis may be established when 4 of the above 7 criteria are present. Criteria 1 through 4 must be persistent for at least 6 weeks before the diagnosis is made.