ASCP Phlebotomy — Questions and Answers
Question 1: What is the recommended angle of needle insertion during routine venipuncture?
- 5–10 degrees
- 15–30 degrees (Correct answer)
- 45–60 degrees
- 60–90 degrees
Correct answer: 15–30 degrees
A 15–30 degree angle allows the needle to enter the vein lumen without penetrating the posterior wall.
Question 2: Which vein is the preferred site for routine venipuncture in the antecubital fossa?
- Cephalic vein
- Basilic vein
- Median cubital vein (Correct answer)
- Brachial vein
Correct answer: Median cubital vein
The median cubital vein is preferred because it is large, well-anchored, and least likely to roll or be painful.
Question 3: How long should a tourniquet remain applied during venipuncture to avoid hemoconcentration?
- Less than 1 minute (Correct answer)
- 2–3 minutes
- 5–7 minutes
- Up to 10 minutes
Correct answer: Less than 1 minute
Prolonged tourniquet use beyond 1 minute causes venous stasis and hemoconcentration, falsely elevating analytes such as proteins and potassium.
Question 4: What is the correct order of draw when collecting multiple tubes via a single venipuncture?
- EDTA → citrate → serum → heparin
- Blood cultures → citrate → serum/SST → heparin → EDTA → fluoride (Correct answer)
- Serum → blood cultures → EDTA → citrate
- Citrate → blood cultures → heparin → EDTA
Correct answer: Blood cultures → citrate → serum/SST → heparin → EDTA → fluoride
The CLSI-recommended order of draw minimizes additive carryover: blood cultures first (sterility), then citrate, serum, heparin, EDTA, and fluoride/oxalate.
Question 5: Which antiseptic is routinely used to cleanse the venipuncture site before needle insertion?
- Povidone-iodine
- Chlorhexidine gluconate
- 70% isopropyl alcohol (Correct answer)
- 3% hydrogen peroxide
Correct answer: 70% isopropyl alcohol
70% isopropyl alcohol is the standard site antiseptic for routine venipuncture and must be allowed to air-dry before needle insertion.
Question 6: Which antiseptic must NOT be used when collecting blood for a blood alcohol (ethanol) level?
- Povidone-iodine
- Chlorhexidine gluconate
- Benzalkonium chloride
- Isopropyl alcohol (Correct answer)
Correct answer: Isopropyl alcohol
Isopropyl alcohol can contaminate the specimen and interfere with ethanol assay results; a non-alcohol antiseptic such as povidone-iodine should be used instead.
Question 7: What is the most common complication of venipuncture?
- Syncope (fainting)
- Hematoma formation (Correct answer)
- Nerve damage
- Inadvertent arterial puncture
Correct answer: Hematoma formation
Hematoma formation is the most common venipuncture complication, resulting from blood leaking into the surrounding tissue when the needle penetrates the vein wall.
ASCP Phlebotomy
What is the recommended angle of needle insertion during routine venipuncture?