A flush syringe assembly (20) comprises a barrel (21) including a cylindrical side wall (22) having an inside surface (23) defining a chamber (25) for retaining fluid, an open proximal end (27) and a distal end (28) including an elongate tip (31) ex-tending distally therefrom having a passageway (32) in fluid communication with the chamber. A plunger (37) including an elongate body portion (38) has a stopper (41) at its distal end. The stopper is slidably positioned in fluid-tight engagement with the inside surface of the barrel for driving fluid out of the chamber. The distai end (61) of the stopper is configured to collapse while fluid is being driven through the passageway through motion of a plunger and to continue to drive fluid through the passageway after motion of the plunger has stopped.