Multiple sample needle assembly with vein indication

Claim 1

A needle assembly for collecting one or more liquid samples from a source for subsequent discharge sequentially into a plurality of evacuated containers, comprising (a) a housing defining a sample collection chamber therein; (b) a front wall on said housing; (c) a rear wall on said housing; (d) an intravenous point spaced from said front wall; (e) a negative pressure point spaced from said rear wall; (f) cannula means extending from said intravenous point to said negative pressure point; (g) means in said cannula means for communicating the lumen of said cannula means with said sample collection chamber; (h) a resilient sleeve extending over the portion of said cannula means extending from said back wall to said negative pressure point; (i) a flange on said sleeve on the end thereof adjacent said rear wall; (j) a passage containing a gas permeable, liquid impermeable filter extending from said chamber through said rear wall; and (k) a flat surface on said sleeve flange for cooperating with said rear wall for blocking gas from passing through said filter; (l) whereby when said intravenous point engages said source, liquid enters said chamber through said communicating means by forcing gas in said chamber through said filter, and when said negative pressure point comes in contact with an evacuated container the stopper thereof causes collapse of said sleeve, moving said sleeve flange against said rear wall for cooperating blockage of said passage.