A venting syringe plunger assembly for use with a syringe system allows for venting of gas from the syringe system during use. The plunger assembly includes a hollow outer sleeve having an interior surface, and an inner stem having an exterior surface. At least a portion of the inner stem is disposed within the outer sleeve so as to be movable (e.g., slidable) within the outer sleeve. A venting passageway is defined between the interior surface of the outer sleeve and the exterior surface of the inner stem. The plunger assembly also includes means for selectively moving the inner stem within the outer sleeve so as to selectively open and close the venting passageway.