[AXS 1114683] Polymorphprep, 250mL
In principle, the greater buoyant density (>1.085 µg/ml) of PMNs (with the exception of basophils) can be exploited for their isolation from lighter mononuclear cells (< 1.077 g/ml). However, the high buoyant density of erythrocytes (1.09-1.11 µg/ml) complicates separation from whole blood using density gradient media like that used for mononuclear cells. However, the high osmolality of Polymorphprep™ causes erythrocytes to lose water and shrink, increasing their effective buoyant density, allowing dextran-aggregated erythrocytes to sediment rapidly through the dense medium. Because the osmotic gradient between the medium and erythrocytes declines as cells sediment further into the medium ( water loss from erythrocytes is greatest at the top of the gradient and decreases progressively with sedimentation) a diatrizoate gradient forms within the density cushion. Within this gradient, PMNs accumulate in a distinct band below mononuclear cells which are retained at the sample/medium interface. The method is effective only from whole undiluted blood, not from a leukocyte-rich fraction.