Described is a needle assembly reuse prevention mechanism comprising a barrier movable between a retracted position and an extended position, a spring coupled to the barrier, a pin formed on the barrier, and a slot receiving the pin. When in the extended position, the barrier substantially covers an opening of a needle assembly storage compartment. The spring forces the barrier in a first direction. The slot has at least one abutment face for abutting the pin and preventing movement of the barrier in the first direction.