BD Vacutainer PST II plasma separator tubes are used to obtain and separate a plasma sample. The tubes are available in plastic in a range of sizes and can be identified by a light green cap. BD PST II contains 17 IU/ml of Lithium Heparin to prevent coagulation of the specimen. The tubes contain an acrylic gel that forms a barrier between the cells and the plasma during centrifugation. BD PST II gel combines the following benefits for increased laboratory efficiency. Enhanced plasma purity demonstrated by a reduction in fibrin, and in measurable white blood cells, red blood cells and platelets. Extended analyte stability as most analytes are stable in the tube for 24hrs at 25C.