An arterial blood collection device is provided having a one-piece plunger rod for use with a blood collection syringe. The plunger rod is hollow, with a closed front end. A self-sealing filter is provided within the closed front end of the plunger rod. Vents are spaced radially about the front end of the plunger rod for fluid communication into the hollow interior thereof. The plunger rod is intended for use in slidable communication within a syringe barrel. In use, the plunger can be retracted within the syringe barrel to form a cavity therein. Upon arterial blood contact, the cavity fills with blood and air can be expelled from the cavity through the vents and the filter and out to ambient air. The plunger rod is a one-piece assembly, eliminating the need for a separate rubber plunger seal.