The stopper-puncturing needle should be completely pushed into the evacuated tube:. A. after the vein is entered. B. while the equipment is being assembled. C. just before the vein is entered. D. prior to anchoring the vein.

The correct answer is:

after the vein is entered (A.)

Explanation:

The procedure in the question describes venopuncture.

Venopuncture is the method of aseptically collecting blood into the right sample containers. Using a stopper-punturing needle and a vacuum tube, the following procedure is followed:

assemble the needle and hub (needle holder)apply the tourniquet and examine the arm for palpable vein, palpate the veinrelease the tourniquet and swab the collection site with 70% alcoholallow the swab to dryreapply the tourniquetinsert the stopper-puncturing needle (attached to hub) into the appropriate veinafter the vein is entered, the stopper-puncturing needle should be completely pushed into the evacuated (vacuum) tubesblood will flow into the tube until vacuum is completely filledpull out the tube and invert gently several times if the tube contains anticoagulantsplace a gauze on the site of puncture (do not press down the gauze)remove the needle and press down the gauze immediatelydispose the needle into the sharps container or appropriatelylabel the tubes.