Abstract: A tube assembly, system and method for biological waste containment for sample collection, and for ultrafiltration collection. In one embodiment, the tube assembly of the present invention includes a first tube, a second tube, a mechanism for securing the first and second tubes, and at least one container for operable connection to one or both of the first and second tubes. The securing mechanism orients the first ends of the first and second tubes in a manner such that the first end of the first tube extends beyond the first end of the second tube an interstitial space is created between the outer diameter of the first tube and the inner diameter of the second tube. The tubing mechanism is utilized for retrieval of a biological fluid through the first tube, flushing the first tube and the second tube with a rinse solution, and extraction of waste through the second tube into a waste container.