Patent ID: 8333711

Claim:
A blood-drawing device comprising: a blood-holding receptacle having a front end; a frustoconically tapered tube of smaller diameter than the receptacle, extending from the front end, and opening rearwardly into the receptacle; a tubular needle fixed on and projecting forwardly from the tube and having a sharpened front tip; a porous, air-permeable limiting element engaged in the tube rearward of the needle, the element being of such a porosity that blood cannot flow through the element; a stop fixing the element in the tube against forward and rearward movement therein; and a ventable plunger shiftable in the receptacle rearward of the element for pressurizing the receptacle, forcing air therethrough, and expelling blood in the tube through the needle, whereby when the plunger is vented blood can flow through the needle into the tube forward of the element by displacing air rearwardly out of the tube through the element into the receptacle and from the receptacle through the plunger.