ERYTHROCYTE SEDIMENTATION-RATE STUDIES IN WHOLE HUMAN BLOOD

Precise measurements have been made of the rate of sedimentation of wh ole blood in which the concentrations of red blood cells and the plasm a proteins have been systematically varied. The contribution of each f actor to the sedimentation process is expressed in terms of three para meters that describe the sedimentation curve: the set-up time, and the slopes of the first and second phases of settling. This analysis affo rds delineation between the onset and the degree of aggregation of the red blood cells as contributors to the usual ESR value, the height of plasma in a 200 nm brood column after 60 min. In terms of the 60 min ESR value, an increase in the haematocrit or albumin concentration inh ibits sedimentation, the latter only slightly, whereas an increase in the concentration of globulin or fibrinogen accelerates sedimentation, with fibrinogen showing the more marked effect.