Diagnosing rheumatoid arthritis: current criteria.

Rheumatoid arthritis is a chronic, systemic inflammatory connective tissue disorder with major effects on the articular system. Causative mechanisms remain unknown, and no specific diagnostic tests are available. Descriptive criteria form the basis of disease classification and diagnosis. Either the 1987 American College of Rheumatology criteria for classification of rheumatoid arthritis or the new rheumatoid arthritis classification tree may be used to diagnose and classify this disease.