A long article from The Journal of Rheumatology...I thought it was interesting.
No single measure such as blood pressure or serum glucose can serve as a "gold standard" in diagnosis and assessment of every individual patient with most rheumatic diseases. Therefore, quantitative clinical assessment requires an index of several measures. Indices have been developed for many rheumatic diseases, including the rheumatoid arthritis (RA) Core Data Set1, Disease Activity Score (DAS)2, and Clinical Disease Activity Index (CDAI)3; the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI)4; Bath Ankylosing Spondylitis Disease Activity Index (BASDAI)5; Birmingham Vasculitis Activity Score (BVAS)6; Western Ontario McMaster Universities Osteoarthritis Index (WOMAC)7; Fibromyalgia Impact Questionnaire (FIQ)8; and many others.