ASPT Specimen Collection Techniques 3 — Questions and Answers
Question 1: What angle should the needle be inserted at during a standard venipuncture?
- 5–10 degrees
- 15–30 degrees (Correct answer)
- 45–60 degrees
- 90 degrees
Correct answer: 15–30 degrees
A 15–30 degree angle of needle insertion allows access into the vein lumen while minimizing the risk of going through the vein.
Question 2: Which additive is found in a royal blue-top tube used for trace element testing?
- Sodium fluoride
- EDTA or no additive (metal-free) (Correct answer)
- Sodium citrate
- Lithium heparin
Correct answer: EDTA or no additive (metal-free)
Royal blue-top tubes contain either EDTA or no additive and are made of metal-free materials to prevent contamination of trace element assays.
Question 3: A tourniquet should be released no later than how long after application?
- 30 seconds
- 1 minute (Correct answer)
- 2 minutes
- 3 minutes
Correct answer: 1 minute
A tourniquet left on longer than 1 minute causes hemoconcentration and can alter analyte concentrations in the specimen.
Question 4: When performing a heel stick on a newborn, which area of the heel is the CORRECT puncture site?
- The posterior curvature of the heel
- The medial or lateral plantar surface (Correct answer)
- The center of the heel pad
- The top (dorsal) surface of the foot
Correct answer: The medial or lateral plantar surface
CLSI guidelines specify the medial or lateral plantar surface of the heel to avoid the calcaneus bone and posterior tibial artery.
Question 5: A patient's vein collapses during blood draw with an evacuated tube. The best corrective action is to:
- Apply a second tourniquet proximally
- Switch to a syringe or butterfly with less vacuum (Correct answer)
- Insert a larger gauge needle
- Ask the patient to pump their fist rapidly
Correct answer: Switch to a syringe or butterfly with less vacuum
Reducing vacuum by using a syringe or butterfly set allows gentler aspiration that prevents vein collapse.
Question 6: Sodium citrate tubes (light blue top) must be filled to the correct volume because:
- Underfilling causes hemolysis
- The citrate-to-blood ratio must be exactly 1:9 (Correct answer)
- Overfilling activates clotting factors
- The tube will crack if underfilled
Correct answer: The citrate-to-blood ratio must be exactly 1:9
Coagulation tests require a precise 1:9 anticoagulant-to-blood ratio; under- or overfilling invalidates PT and PTT results.
Question 7: Which of the following correctly describes the proper bevel position at the start of venipuncture?
- Bevel facing down toward the skin
- Bevel facing up toward the ceiling (Correct answer)
- Bevel angled at 90 degrees to the vein
- Bevel position does not matter
Correct answer: Bevel facing up toward the ceiling
The bevel should face up so the needle enters the vein smoothly, allowing blood to flow freely into the lumen.
ASPT Specimen Collection Techniques 3
What angle should the needle be inserted at during a standard venipuncture?