Abstract: A centrifuge tube assembly comprising an elongated vial having an open upper end and a closed lower end with a lid mounted on the upper end thereof. The lid has a central opening formed therein which rotatably receives an elongated inner tube extending downwardly into the vial with the bottom of the inner tube being received by an upstanding bottom tube. The lower end of the inner tube has a pair of vertically spaced-apart upper and lower ports. The bottom tube has a pair of upper and lower ports formed therein which are radially offset with respect to one another. A tube actuator is secured to the upper end of the inner tube to facilitate the rotation of the inner tube between first and second positions. When the inner tube is in its first position, the lower ports of the inner tube and bottom tube are in register. When the tube actuator is in its second position, the upper ports of the inner tube and the bottom tube are in register.