Separation of Human Monocytes from a Leukocyte-Rich Plasma

Human peripheral blood monocytes are isolated by flotation from a dense leukocyte-rich plasma (LRP) through two lower-density barriers prepared from OptiPrep. The separation from lymphocytes depends on the more rapid rate of flotation of the monocytes because of their slightly lower density and larger size. The method works optimally only with fresh (within 2 h of drawing) EDTA-anticoagulated blood.