Westergren method the most common method for testing the erythrocyte sedimentation rate ; four volumes of whole blood are mixed with one volume of sodium citrate anticoagulant-diluent solution and placed in a tube graduated in millimeters from 0 to 200, filling to the 0 mark; the tube is placed in a vertical position for 1 hour and the fall of the level of red cells is recorded in mm/hr.