Lymphocyte Separation Medium (LSM) is a ready to use, sterile based on Ficoll, a polymer with a high molecular weight (400.000) and a perfectly defined density of 1.077 +/- 0.001. The LSM is intended for the preparation of lymphocyte solutions from whole blood. The LSM should be kept at 4 °C and away from light. A certificate of quality can be made available on request.