Histopaque™1077 is a solution of polysaccharide (Ficoll-400) and a radiopaque contrast medium (sodium diatrizoate).Low viscosity of Ficoll® is used for lymphocyte isolation procedure involving a short, low speed centrifugation. A solution of Ficoll® and sodium metrizoate of the proper density and osmotic strength is placed in a centrifuge tube. Blood is layered on top, and the two-phase system was centrifuged at a low speed for a short time. The erythrocytes and granulocytes sediment to the bottom of the tube. Because of lower density, the lymphocytes are found at the interface between the plasma and the Ficoll-Paque with other slowly sedimenting particles (platelets and monocytes). The ficoll-sodium metrizoate centrifugation procedure is an easy one-step, rapid, reproducible method for the preparation of viable lymphocytes in high yield. Sodium diatrizoate can be substituted as sodium metrizoate.
Ficoll is used in isolating lymphocytes from whole blood in areas such as histocompatability testing, in vitro cell-mediated immunity assays, and other procedures requiring pure lymphocyte preparations. Since this method can be adapted to very small volumes of blood, it is particularly suitable for isolation of lymphocytes where only limited quantities of blood are available, such as from cadavers and small children. Because of the rapidity and simplicity of the method, it is also the method of choice in emergency tissue typing procedures.