IMDM (Iscove's Modified Dulbecco's Medium) is utilized not only for more specialized cell types but also as the basis for some of the more unique serum-free media formulations. The original formulation designed by Iscove and associates, demonstrated that erythrocytes and macrophage precursor cells (e.g. primary Haemopoietic Cells) could be cultured in a totally defined serum-free medium when supplemented with albumin, lecithin, selenium and transferrin. IMDM is a modification of DMEM (Dulbecco's Modified Eagle's Medium) containing selenium, additional AA's, vitamins and other components. IMDM is a highly enriched synthetic media well-suited for rapidly proliferating and high-density cell cultures in a 5% CO2 atmosphere.