. . . "ACR improvement criteria is a standard assessment developed by the American College of Rheumatology to measure the signs and symptoms of RA. ACR20, ACR50, ACR70 represent the percentage of reduction (20 percent, 50 percent, 70 percent) in certain RA signs and symptoms, such as the number of tender and swollen joints, pain, patients??? and physicians??? global assessments and certain laboratory mar" .