Abstract: A modular syringe assembly can include: a tubular syringe barrel having a proximal end and a distal end, the tubular syringe barrel defining a longitudinal axis; a plunger slidable within the tubular syringe barrel; and a cap assembly including a stopper portion and a Luer tip, the stopper portion receivable in the distal end of the tubular syringe barrel, the stopper portion defining a vent window. The cap assembly can be slidable within the tubular syringe barrel along the longitudinal axis between a sealed position where the vent window is covered by the tubular syringe barrel to prevent venting between the cap assembly and the tubular syringe barrel, and a vented position where the vent window forms a vent between the cap assembly and the tubular syringe barrel. Other features and methods are also described.