A Platelet Rich Plasma separator assembly is disclosed. The assembly can include a cylindrical outer wall closed at the top by an upper plate and closed at the bottom. A bottom plate having an upper surface sloped down to a central opening. The top edge of the inner wall terminates at a distance from the upper plate to define an annular erythrocyte passageway therebetween. The inner wall has an outer surface and an inner surface that slopes radially inward from its top edge to its bottom at an angle of from 0.2 to 5 degrees with a central axis of the inner wall. A cylindrical depth filter is positioned between the inner surface of the outer wall and the outer surface of the inner wall in communication with the inner wall through the erythrocyte passageway.