An access device for accessing a lumen of a blood vessel includes a hub, a needle having a tip and a guidewire having a rear end portion and a front end portion. The hub has a longitudinal axis, a main channel, a guidewire channel and an auxiliary channel. The needle has a proximal end and a needle lumen extending between the tip and the proximal end. The proximal end is secured to a distal end of the hub. The needle lumen is in fluid communication with the main channel. The guidewire has a rear end portion and a front end portion. The front end portion is positioned in the guidewire channel proximally relative to a sealing mechanism in an initial configuration. The sealing mechanism substantially limits fluid flow from the main channel through the guidewire channel.
