Distinctions Between Diagnostic and Classification Criteria?

Rheumatologists face unique challenges in discriminating between rheumatologic and non-rheumatologic disorders with similar manifestations, and in discriminating among rheumatologic disorders with shared features. The majority of rheumatic diseases are multisystem disorders with poorly understood etiology; they tend to be heterogeneous in their presentation, course, and outcome, and do not have a single clinical, laboratory, pathological, or...