Rheumatism Association Criteria for the Classification of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is among the most common forms of chronic inflammatory arthritis. RA affects about 1% of adults, and it is two to three times more prevalent in women than in men. RA may begin as early as infancy, but onset usually occurs in the fifth or sixth decade. There are no specific laboratory tests for RA; diagnosis depends on a constellation of signs and symptoms that can be supported by serology and radiographs. Involvement of the small joints of the hands and feet is often the key to the diagnosis. Specific clinical criteria have evolved [see Table 1], but in practice, diagnosis is established by careful observation of the pattern of disease activity over time.