TwinSpin centrifugation tubes pre-filled with Density Gradient Medium (DGM) can be used for an optimal separation peripheral blood mononuclear cells from whole blood and bone marrow. The TwinSpin is comprised of a standard 15 ml and an inner tube. The inner tube has an open bottom which is submersed in the DGM. Diluted anti-coagulated blood or bone marrow can simply be pipetted into the TwinSpin. The sample lays on top of the DGM inside the inner tube. During centrifugation, Leukocytes, lymphocytes and PBMCs are separated from unwanted erythrocytes and granulocytes, depending on the DGM. The result is an inter-phase enriched with target cells above the DGM. The erythrocytes will sediment through the density gradient media out of the inner tube at the bottom of the outer tube. When separation is complete, just remove the inner tube. The elastic cap functions as valve. By pushing the cap down, the collection tube becomes a pipette. The contents can be collected drop by drop. Prefilled with DGM of your choice.