In density isolation, or buoyant density separation, different cell populations are isolated by their inherent densities. It is a particularly reliable and established whole blood separation method at small to larger scales. The hydrophilic polysaccharide FicollTM, for example, is a commonly used density gradient medium for separating peripheral blood components, such as lymphocytes and red blood cells. Various manufacturers have developed more specialized media, such as those incorporating antibodies, for more specific isolations.