A biological component concentration fluid assembly includes magnetizing microparticles that are surface-activated to bind with (or are bound to) a biological component; a multi-fluid density gradient column with a first fluid layer, a second fluid layer, and a third fluid layer; and a magnet to attract and draw the magnetizing microparticles from the first fluid layer, through the second fluid layer, and into the third fluid layer. The first fluid layer has a first fluid density, and a second fluid layer has a second fluid density that is greater than the first fluid density, and is positioned beneath the first fluid layer. A third fluid layer has a third fluid density that is greater than the second fluid density and is positioned beneath the second fluid layer. The second and third fluid layers in this example are formulated to interact with the surface of the magnetizing microparticles.