4. Venipuncture

Question 1

What needle size and length are routinely used for blood collection?

Answer 1

1 or 1½” length 20 to 22 G except for butterfly needles which are usually 1 inch.

Question 2

When should the protective sheath be removed from a blood collection needle? Why?

Answer 2

Immediately prior to penetration of the skin to ensure the needle remains sterile.

Question 3

Why are tourniquets used in blood collection?

Answer 3

They constrict the veins causing them to become more prominent both visually and to touch.

Question 4

Is it important to make sure the plunger is flush with the nozzle of the barrel when using a syringe? WHY?

Answer 4

To make sure there is no possibility that air will be injected into the patient’s vein.

Question 5

List three important items to remember when using vacutainer collection tubes

Answer 5

i) must not be out-of-date to assure sterility, vacuum and anticoagulant effectiveness
ii) must be properly filled to assure correct anticoagulant to blood ratio
iii) if they contain an anticoagulant or clot activator they must be adequately mixed immediately after collection

Question 6

Describe how to dispose of used needles.

Answer 6

Do not recap. Do not break. Twist off into a puncture-proof container using a needle removal device.

Question 7

List the 5 pieces of information which should be on every tube of blood.

Answer 7

patient’s full name
patient’s I.D. number
date and time of collection
name of the test (s) to be done on the sample collector’s initials

Question 8

When should the specimen be labelled?

Answer 8

Immediately after the blood has been mixed and before leaving the bedside.

Question 9

A technologist receives two un-labelled specimens wrapped in two different requisitions. How should this situation be handled?

Answer 9

New requisitions and new, properly labelled specimens should be recollected. Never make identity assumptions

Question 10

During blood collection, when should the tourniquet be released? Why?

Answer 10

Once blood has entered the vacutainer tube or syringe. The tourniquet should be on for no longer than 1 minute to prevent hemoconcentration. As well, it must be released before the needle comes out of the arm to prevent a hematoma from forming.

Question 11

State whether the following statements are true or false. If the statement is false, correct the underlined phrase to make it true.

The veins in the antecubital fossa area must be visible to be chosen for venipuncture.

Answer 11

False, palpatable

Question 12

State whether the following statements are true or false. If the statement is false, correct the underlined phrase to make it true.

The bevel of the needle should be facing down when entering the vein.

Answer 12

False, up

Question 13

State whether the following statements are true or false. If the statement is false, correct the underlined phrase to make it true.

A good choice of vein for venipuncture is one which feels flat and rolls when touched.

Answer 13

False, full and stable

Question 14

State whether the following statements are true or false. If the statement is false, correct the underlined phrase to make it true.

You know the needle is in the vein when you feel an ease of penetration of the needle.

Answer 14

True

Question 15

State whether the following statements are true or false. If the statement is false, correct the underlined phrase to make it true.

Syringe needles have two pointed ends whereas vacutainer needles have a single pointed end.

Answer 15

False, one pointed end, two pointed ends

Question 16

State whether the following statements are true or false. If the statement is false, correct the underlined phrase to make it true.

Failing to have the bevel of the needle completely in the vein is acceptable .

Answer 16

False, will cause a hematoma to form

Question 17

State whether the following statements are true or false. If the statement is false, correct the underlined phrase to make it true.

Repositioning a needle in a patient’s arm because the vein has been missed is an acceptable practice even if the patient finds this painful.

Answer 17

False, as long as it is done in such a way that prevents tissue scarring and is not painful to the patient

Question 18

State whether the following statements are true or false. If the statement is false, correct the underlined phrase to make it true.

Collapsed veins may be prevented by using smaller needles and a syringe technique.

Answer 18

True

Question 19

12. List at least six specimens which should be transported to the lab on ice.

Answer 19

ACTH, acetone,Lactic acids(lactate), ammonia, catecholamines, renin, ionised calcium, Proteins S and C, Factor V, Antithrombin III, Homocysteine

Question 20

List at least three specimens which should be transported to the lab in the dark.

Answer 20

bilirubin, Vitamins A and B12

carotenes

erythrocyte protoporphyrins

Question 21

Which specimen should be kept at 37oC?

Answer 21

Cold agglutinins

Question 22

When using a syringe method, what draws the blood into the syringe?

Answer 22

The blood will enter the syringe when you pull back on the plunger.

Question 23

When would a syringe or butterfly method be preferred over the vacutainer method?

Answer 23

When veins have a tendency to collapse, because you are able to control the pressure using a syringe.