The claimed subject matter comprises a device to collect and preserve cells comprising of: (1) a collection container comprised of a tube having an open end and a closed end, a closure in the open end of the tube, a vacuum drawn to a predetermined level inside the container； and (2) compounds including an anticoagulant agent and a fixative agent, wherein the compounds are in a sufficient amount to preserve said cells” original morphology and antigenic sites without significant dilution of said cells, and thereby allowing said cells to be directly analyzed by a flow cytometer without further treatment. The claimed subject matter further comprises of a method of making a collection device for cells comprising of: (1) providing a tube having an open end and a closed end； (2) preloading compounds including: an anticoagulant agent, and a fixative agent into the tube, wherein the compounds are in a sufficient amount to preserve the cells” original morphology and antigenic sites without significant dilution of the cells, and thereby allowing the cells to be directly analyzed by a flow cytometer without further treatment； (3) inserting a closure into the open end of the tube； and (4) drawing a vacuum inside the tube to a predetermined level to form the collection device.
