For containing a biological fluid and draining a constituent of the biological fluid, a kit includes a barrel, a piston assembly, a removable element, which is configured to move the piston assembly, a drainage element, which interacts with the piston assembly, and an interacting element, which interacts with the piston assembly. The kit allows for fluid separation without risk of contamination from the biological fluid itself or contamination of the biological fluid itself. Further, the kit offers the advantage of involving no needles or other sharp elements.
