a device for expelling a fluid through a needle mounted on a hub includes an elongated luer member that has a distal portion dimensioned to engage the needle hub to provide fluid communication between the luer member and the needle . an adapter anchors the luer member within the device . slidingly mounted on the adapter is a cylindrical - shaped inverted plunger that is movable thereon between an advanced position and a withdrawn position . a needle guard is biased by a biasing member to extend distally from the luer member when the plunger is in the advanced position . the guard is selectively engageable with the plunger to be retracted to expose the distal portion of the luer member for fluid engagement with the needle hub when the plunger is moved to the withdrawn position .