A cap assembly is disclosed for use with a lock solution delivery device. The cap assembly includes a housing defining a receptacle and having an inlet end and an outlet end. A plunger is movable axially within the receptacle from a retracted position to an advanced position and is rotatably supported within the receptacle from a first position to a second position. The plunger includes an axial extension configured to non-rotatably engage a syringe connected to the inlet end of the housing. The plunger is positioned to move from the first position to the second position in response to rotatable detachment of a syringe from the inlet end of the housing.