E1: A blood collection kit comprising: a needle holder, a needle assembly engage able with needle holder where the needle pierce able resalable closure sealing engaged with end of flexible tubing.

E2: A blood collection bag assembly comprising a flexible bag for collecting a volume of blood, flexible tubing extending from and communicating with the bag, the flexible tubing having an end remote from the bag, and a connector secured to end of flexible tubing remote from bag, connector comprising an inner fitting supportingly engaged within end of flexible tubing remote from bag, fitting preventing flexible tubing from collapsing, and thereby facilitating secure engagement of closure with flexible tubing.

E3: A cap comprising a cylindrical sidewall surrounding end of flexible tubing and an annular end wall extending inwardly from cylindrical sidewall, annular end wall securely engaging closure for sealing flexible tubing, wherein the inner fitting and the cap are separate from one another, cylindrical sidewall of cap being forcibly engaged over end of flexible tubing for securely gripping end of flexible tubing between cylindrical sidewall and inner support.