Learn how to use this product Lymphocyte Separation Medium (LSM) is a sterile, ready-to-use reagent for the in vitro isolation of lymphocytes and monocytes from whole human blood, bone marrow, buffy coats, and other starting materials. The separation solution contains Ficoll™, a hydrophilic polymer with a molecular weight of 400000 Dalton. It is used for the production of density gradients for the separation of cells and sub-cellular components, which sediment during centrifugation due to gravity.