BD Vacutainer Plasma tubes contain Lithium Heparin and are used to obtain a plasma sample. The tubes are available in a range of sizes and can be identified by a green cap. The concentration of the Lithium Heparin additive in BD Vacutainer Plasma tubes is 17 International Units of Heparin/ml of blood. The additive in the Plus tube is spray coated on the inner wall. BD Vacutainer Heparin tubes can be centrifuged immediately after collection.