CSC Equipment Operation & Maintenance 2 — Questions and Answers
Question 1: What is the correct procedure when a vacuum tube fails to fill during venipuncture?
- Withdraw the needle and try a new site
- Apply pressure to the tube to force blood flow
- Replace the tube with a new evacuated tube without withdrawing the needle (Correct answer)
- Increase tourniquet pressure and wait
Correct answer: Replace the tube with a new evacuated tube without withdrawing the needle
If a vacuum tube fails to fill, it should be replaced with a new evacuated tube without removing the needle from the vein.
Question 2: Which needle gauge is most commonly used for routine adult venipuncture?
- 18 gauge
- 21 gauge (Correct answer)
- 25 gauge
- 28 gauge
Correct answer: 21 gauge
A 21-gauge needle is the standard choice for routine adult venipuncture, balancing blood flow rate with patient comfort.
Question 3: When using a winged infusion (butterfly) set, what additional step is required when collecting a coagulation tube?
- Fill the tube twice as fast
- Use a discard tube first to eliminate air from the tubing (Correct answer)
- Invert the tube immediately after collection
- Attach a syringe instead of a vacuum tube
Correct answer: Use a discard tube first to eliminate air from the tubing
A discard tube must be drawn first when using a butterfly set to purge the dead-space air and ensure proper blood-to-anticoagulant ratio in the coagulation tube.
Question 4: How should a lancet be disposed of after a capillary puncture?
- In a regular trash bin with a cap replaced
- In a sharps container immediately (Correct answer)
- In a biohazard bag for soft waste
- Recapped and given to a supervisor
Correct answer: In a sharps container immediately
Used lancets are sharps and must be discarded immediately into an approved sharps container to prevent needlestick injuries.
Question 5: What does 'hemolysis' in a blood specimen most often indicate about collection technique?
- The tourniquet was left on too long
- The tube was filled in the wrong order
- Excessive force was used drawing blood into a syringe or through a small-gauge needle (Correct answer)
- The patient was not fasting
Correct answer: Excessive force was used drawing blood into a syringe or through a small-gauge needle
Hemolysis commonly results from excessive aspiration force, using too small a needle gauge, or vigorous mixing, which ruptures red blood cells.
Question 6: Which action should be taken if a centrifuge becomes visibly unbalanced during operation?
- Open the lid immediately and redistribute tubes
- Turn off the centrifuge and allow it to stop on its own before opening (Correct answer)
- Add more tubes to balance the load while running
- Increase the speed to push through the imbalance
Correct answer: Turn off the centrifuge and allow it to stop on its own before opening
An unbalanced centrifuge must be turned off and allowed to stop completely before the lid is opened to prevent injury from the spinning rotor.
Question 7: What is the purpose of the flange on a blood collection tube holder?
- To secure the needle cap
- To provide a grip surface for pushing tubes onto the needle and removing them (Correct answer)
- To indicate the expiration date of the holder
- To prevent blood from refluxing into the patient
Correct answer: To provide a grip surface for pushing tubes onto the needle and removing them
The flange (wings) of the tube holder gives the phlebotomist leverage to push tubes onto the needle and to eject used tubes safely.
CSC Equipment Operation & Maintenance 2
What is the correct procedure when a vacuum tube fails to fill during venipuncture?