- The necessary degree of disease activity at enrollment should be confirmed by a finding of 10 or more swollen joints, 12 or more tender joints, and one of the following two criteria: a Westergren erythrocyte sedimentation rate of at least 28 mm per hour or a serum C-reactive protein level of more than 2.0 mg per deciliter; or morning stiffness for at least 60 minutes.