Embodiments of the invention are directed to flush syringe assemblies (100) comprising an integrated contamination-prevention device (170) integrated with device connector flushing positioned so that the practitioner cannot forget to apply disinfectant. The flush syringe assemblies comprise a barrel (110) with an elongate plunger rod (120) disposed therein and a cap (130) comprising a passageway (134). The plunger rod (120) includes a stopper (150) of which at least a portion (155) can be embedded in the passageway of the cap (130) to form a plug (155) in the cap (130).