Abstract
The viscosity of plasma (PV) was investigated in 27 outpatients with classical or definite rheumatoid arthritis (RA) according to the American Rheumatism Association (ARA) criteria. The measurements showed a significantly raised PV in patients with RA (p less than 10(-5)) compared with a control group. There was a positive correlation between the PV and the blood erythrocyte sedimentation rate (B-ESR), and the increase in the PV is largely explained by increased concentrations of the plasma proteins, fibrinogen, and IgG.