Methods of Blood Collection

Question 1

Method of choice in pediatric patients. Also useful in obese adults, patients with severe burns, and thrombotic tendencies

Answer 1

Capillary Puncture

Question 2

Where is the site for capillary punctures?

Answer 2

Heel of infants
Palmer surface of the distal phalanx of the middle or ring finger.

Middle finger is first choice

Question 3

Best method for blood collection?

Primary source of specimen for clinical laboratory analysis?

Answer 3

Venipuncture Method

Question 4

What is needed for capillary puncture?

Answer 4

• Sterile gauze pads
• 70% ETOH or Betadine solution
• Lancet
• Capillary tubes or QBC Star tube

Question 5

Is the lancet used to stab center of the finger or off center of the finger

Answer 5

Off center

Question 6

During capillary puncture, why is the first drop of blood wiped away?

Answer 6

To avoid dilution of blood with tissue fluid.

Dilution will cause inaccurate results.

Question 7

At what depth is the lancet not to exceed?

Answer 7

2 mm

Question 8

Should blood samples be obtained from IV sites?

Answer 8

NO

Question 9

Approximately how high above the antecubital area is the tourniquet placed?

Answer 9

2 - 3 inches

Question 10

What can be used for patients whose veins are difficult to locate?

Answer 10

Blood pressure cuff (30 mm/Hg)

Question 11

At what angle is the needle introduced into the vein?

Answer 11

15-degree

Question 12

How is the selected vein fixed or held taut?

Answer 12

By placing the thumb under puncture site with downward pressure

Question 13

How do you prevent clotting in the tube?

Answer 13

Gently inverting the tube with an anticoagulant

Question 14

what must be used to obtain a whole blood specimen for testing?

Answer 14

An Anticoagulant

Question 15

Liquid anticoagulant used in purple tops.

Most widely used anticoagulant.

Answer 15

Ethylenediaminetetracetic Acid (EDTA)

Question 16

How long can a sample with the EDTA anticoagulant be refrigerated?

Answer 16

24 hours

Question 17

What does it mean that EDTA is a chelating agent?

Answer 17

It binds to calcium so blood cannot clot

Question 18

A powder anticoagulant used in light blue tops.

typically used for coagulation studies.

Answer 18

Sodium Citrate

Question 19

What labs are included in coagulation studies?

Answer 19

• Prothrombin Time (PT)

- Partial Thromboplastin Time (PTT)

Question 20

liquid or powder Anticoagulant in green tops.

Typically used for plasma and Chemistry testing.

Answer 20

heparin

Question 21

Plasma studies and chemistry testing include:

Answer 21

Ammonia
Adrenocorticotropic hormone (ACTH)

Question 22

How does heparin work as an anticoagulant?

Answer 22

Inhibits the clotting enzyme, thrombin, by creating antithrombin.
Prevents prothrombin from converting to thrombin.

Question 23

Which color tube does not contain anticoagulant or additives

Answer 23

Red tops

Question 24

What are red tops mainly used for?

Answer 24

• Chemistry
• Serology
• Blood Bank

Question 25

These tubes do not contain anticoagulants.
Contain a serum separator gel.
Primarily used for chemistry testing.

Answer 25

Serum Separator Tube (SST)/Gold Top, Tiger Top, HIV tube (Red/Yellow)

Question 26

This anticoagulant is found in grey tops.
Used for glucose studies.
Inhibits Glycolosis.

Answer 26

Sodium Fluoride.

Question 27

Which samples are drawn first, additive containing tubes or non-additive containing tubes?

Answer 27

Draw specimens into non-additive containing tubes before drawing specimens in additive containing tubes.

Question 28

What is the order for filling additive-containing tubes?

Answer 28

Blood culture tubes, Blue Tops, Red Tops, SST, Green Top, Lavender Top, and Gray Top