Blood collecting assembly

Claim 1

A holder, cannula and valve assembly for collecting blood, comprising: a holder having a generally tubular longitudinally extending passageway open at one end and having an end portion opposite the open end, a cannula extending longitudinally and connected to the end portion of said holder, said cannula having an interior marginal end terminating in the passAgeway at a piercing end and having an exterior marginal end extending exteriorly of said holder and terminating at a vein-piercing end, said interior marginal end having an opening through which blood can pass, valve means received about said interior marginal end of said cannula and connected to said holder, said valve means including air vent means providing communication from said cannula opening, through said air vent means, into said passageway, and to the atmosphere, and mounting means for said valve means connected to the end portion of said holder and enabling lengthwise shifting movement of the valve means relative to the cannula from a first position in which said cannula opening communicates with the atmosphere to provide a blood telltale at said cannula opening when said vein-piercing end has pierced the vein of a patient to a second position at which said cannula opening is closed off from the atmosphere by said valve means to prevent additional blood from passing out of said cannula opening until blood is to be collected, said valve means being composed of a material which is cannula pierceable, resealable and sufficiently transparent to enable visual observation of the blood telltale through the valve means.