A plasma concentrator having a concentrator chamber, concentrator gel beads, a filter, and an agitator. The agitator end is positioned in the concentrator chamber and supported for rotation about its central axis and for reciprocal movement along its central axis. A filter is selected to block effective flow of plasma therethrough under ambient gravity conditions and permit plasma and plasma concentrate flow therethrough under centrifugal forces of the separation gravity. A method concentrates plasma by removing water without significantly denaturing the fibrinogen in the plasma. Then centrifugal force can be applied to the concentrated plasma in an amount sufficient to separate a substantial portion of the plasma concentrate from the beads.