A medical device configured as a blood collection tube holder, the device having a body with two spaced-apart, oppositely facing, coaxially aligned needles including a forwardly facing venipuncture needle and a rearwardly facing fluid discharge needle, the two needles being held by first and second needle holders separated by a compressible fluid seal defining part of a fluid path between the two needles and the two needle holders. The body also includes a discharge needle displacement member that is manually repositioned following removal of the last blood tube holder so that the discharge needle displacement member contacts the second needle holder and displaces the second needle holder and the fluid discharge needle laterally inside the body to initiate retraction of the venipuncture needle into a rearwardly projecting needle retraction chamber.
