The zeta sedimentation ratio (ZSR) is a measurement similar to the determination of the erythrocyte sedimentation rate (ESR) but possesses sevaral advantages. It is unaffected by anemia and responds in a linear manner to increase in fibrinogen and/or gamma globulin. The normal range is identical for males and females. A blood sample, contained within a vertically oriented capillary tube, is subjected to four cycles of dispersion and compaction. At the conclusion of this process, the hematocrit of the blood in the red cell-containing portion of the capillary tube is measured. This hematocrit, a measure of the closeness with which red cells will approach each other under a standardized stress, is the ZSR.