CSC Collection Procedures & Techniques 3 — Questions and Answers
Question 1: When performing a venipuncture, which site is preferred for routine blood collection in an adult patient?
- Cephalic vein of the forearm
- Median cubital vein of the antecubital fossa (Correct answer)
- Basilic vein of the upper arm
- Dorsal hand vein
Correct answer: Median cubital vein of the antecubital fossa
The median cubital vein in the antecubital fossa is the first-choice site because it is large, well-anchored, and least painful for most patients.
Question 2: A collector notices that a urine specimen has a blue-green color. What does this most likely indicate?
- Normal concentrated specimen
- Possible presence of methylene blue or amitriptyline (Correct answer)
- Specimen is too dilute for testing
- Contamination with toilet bowl water
Correct answer: Possible presence of methylene blue or amitriptyline
Blue-green urine can result from certain medications such as methylene blue, amitriptyline, or indomethacin, and should be noted in the remarks section.
Question 3: What is the maximum time allowed between blood collection and centrifugation for serum separator tube (SST) specimens?
- 15 minutes
- 30 minutes
- 60 minutes (Correct answer)
- 2 hours
Correct answer: 60 minutes
SST specimens should be centrifuged within 60 minutes of collection to prevent cellular metabolism from altering analyte concentrations.
Question 4: Which needle gauge is most commonly used for routine adult venipuncture?
- 16 gauge
- 18 gauge
- 21–22 gauge (Correct answer)
- 25 gauge
Correct answer: 21–22 gauge
21–22 gauge needles are standard for routine adult venipuncture, balancing adequate flow rate with patient comfort and minimizing hemolysis.
Question 5: When collecting blood from a patient with an IV line in the arm, what is the best practice?
- Draw from the same arm 2 inches above the IV site
- Turn off the IV for 2 minutes, then draw below the IV site
- Collect from the opposite arm or a site distal to the IV after stopping the infusion for at least 2 minutes (Correct answer)
- Collect from the IV line directly using a Vacutainer adapter
Correct answer: Collect from the opposite arm or a site distal to the IV after stopping the infusion for at least 2 minutes
Drawing from the opposite arm or below the IV site (after stopping the infusion for at least 2 minutes) prevents IV fluid contamination of the specimen.
Question 6: How should a capillary blood specimen be collected from a neonate's heel?
- Puncture the center of the heel pad
- Puncture the medial or lateral plantar surface of the heel (Correct answer)
- Puncture the posterior curve of the heel
- Puncture the toe of the foot for convenience
Correct answer: Puncture the medial or lateral plantar surface of the heel
CLSI guidelines specify puncturing the medial or lateral plantar surface of the heel to avoid bone and minimize risk of osteomyelitis.
Question 7: What does a 'rolling vein' mean and how should a collector respond?
- A vein that moves laterally when the needle approaches; anchor the vein by pulling skin taut below the puncture site (Correct answer)
- A vein that collapses upon needle entry; use a larger gauge needle
- A vein with excessive valves; puncture above the valve
- A vein that is too superficial; choose a deeper site
Correct answer: A vein that moves laterally when the needle approaches; anchor the vein by pulling skin taut below the puncture site
A rolling vein moves sideways instead of staying in place; anchoring the skin below the site with the thumb stabilizes it for successful puncture.
CSC Collection Procedures & Techniques 3
When performing a venipuncture, which site is preferred for routine blood collection in an adult patient?