A method for obtaining the contents of a fluid-holding vessel having a cap secured to an open end thereof. The method includes penetrating a surface of the cap with a fluid transfer device and forming one or more air passageways between the penetrated surface of the cap and the fluid transfer device to allow air to be vented from the vessel. At least a portion of the contents of the vessel is then drawn into the fluid transfer device before the fluid transfer device is removed from the vessel.