Method and device for separating blood components

Claim 1

A barrier device for separating the sera, fibrin and heavier phases with the latter phase including red cells, white cells and platelet elements and wherein the phases have differing specific gravities from a blood sample within a tube or tubular holder, said barrier device comprising a circular member having an outer diameter less than the inner diameter of said tube with the diametric difference therebetween allowing gravity motivated movement of said barrier device coaxially in said tube with fluidic flow of the blood sample components past the peripheral edge of said circular member, said barrier device having a specific gravity intermediate that of the sera and the heavier phases of the blood sample to be separated, having at least one opening through said circular member large enough to allow the flow of at least the lighter components therethrough when the tube and said member are in an environment conducive to component separation based upon specific gravity differences along the axis of said tube, and having means including a series of projections spaced around the peripheral edge extending substantially in an axial direction from said circular member, , whereby application of a migration inducing environment such as by centrifugal force to said tube will cause said member to migrate along the length of said tube while passing through the blood sample phases until it occupies a position intermediate the sera and the other blood sample phases.