The present invention is directed to a vascular blood containment that allows a user to determine whether a blood vessel has been accessed and which provides access to the vessel. The vascular blood containment device includes a compression seal having increased reliability. The seal permits the passage of gas but prevents the passage of liquid. A valve providing access to a blood vessel through the blood containment device is configured to conform to an inner profile formed around a bore of the distal end of the outer housing. The configuration of the device permits the blood containment chamber to fill properly when the distal end of the blood containment device is positioned below the proximal end of the device.