vacutainer A test tube which is either a sterile glass or plastic tube with a closure that is evacuated to create a vacuum inside the tube facilitating the draw of a predetermined volume of liquid. Most commonly used to draw a blood sample directly from the vein, these also are used to collect urine samples. Vacutainer tube may contain additives designed to stabilize and preserve the specimen prior to analytical testing. Person: Jie Zheng, Chris Stoeckert http://en.wikipedia.org/wiki/Vacutainer container