VACUETTE® Heparin tubes
The interior of the tube wall is coated with lithium heparin, ammonium heparin or sodium heparin. The anticoagulant heparin activates antithrombins, thus blocking the coagulation cascade and producing a whole blood / plasma sample instead of clotted blood plus serum.
Plasma tubes with lithium heparin and gel contain a barrier gel in the tube. The specific gravity of this material lies between that of the blood cells and plasma. During centrifugation the gel barrier moves upwards providing a stable barrier separating the plasma from cells. Plasma may be aspirated directly from the collection tube, eliminating the need for manual transfer to another container. This barrier allows for the stability of certain parameters in the primary tube under the recommended storage conditions for up to 48 hours.
Lithium determinations should not be performed in VACUETTE® Lithium Heparin tubes. Ammonium determinations should not be performed in VACUETTE® Ammonium Heparin tubes. (Ammonium Heparin tubes are not available in U.S.A.)