PCT Lab Procedures 4 — Questions and Answers
Question 1: A PCT is about to perform venipuncture on a patient who has an IV infusing in the left arm. What is the best action?
- Draw from the left arm above the IV site
- Draw from the right arm (Correct answer)
- Stop the IV, wait 2 minutes, then draw from the left arm
- Draw from the left hand
Correct answer: Draw from the right arm
Drawing from the arm opposite the IV site prevents IV fluid from diluting the specimen and producing inaccurate results.
Question 2: Which color tube top is used for a complete blood count (CBC)?
- Red
- Light blue
- Lavender (purple) (Correct answer)
- Gray
Correct answer: Lavender (purple)
Lavender/purple tubes contain EDTA, which prevents clotting and preserves blood cells for hematological analysis.
Question 3: A rapid strep test is negative but the patient's symptoms strongly suggest strep throat. What should the PCT do?
- Repeat the rapid test immediately
- Report the negative result and document it
- Inform the nurse, as a throat culture may be needed for confirmation (Correct answer)
- Discard the swab and collect a new specimen from the tonsils only
Correct answer: Inform the nurse, as a throat culture may be needed for confirmation
Rapid strep tests have a false-negative rate; a negative result with high clinical suspicion warrants a confirmatory throat culture.
Question 4: When labeling a blood specimen tube, the PCT should:
- Label tubes before drawing and then fill them
- Label tubes at the bedside immediately after collection (Correct answer)
- Label tubes in the lab upon arrival
- Have the nurse label all tubes in advance
Correct answer: Label tubes at the bedside immediately after collection
Labeling at the bedside immediately after collection prevents specimen mix-ups, a critical patient safety requirement.
Question 5: A urine dipstick test shows positive nitrites. This finding most likely indicates:
- Kidney stones
- Bacterial infection in the urinary tract (Correct answer)
- High protein levels
- Blood in the urine
Correct answer: Bacterial infection in the urinary tract
Nitrites are produced when gram-negative bacteria convert urinary nitrates, making a positive result a strong indicator of UTI.
Question 6: What is the maximum recommended time a tourniquet should remain in place during venipuncture?
- 30 seconds
- 1 minute (Correct answer)
- 3 minutes
- 5 minutes
Correct answer: 1 minute
A tourniquet left on longer than one minute causes hemoconcentration, which can falsely elevate many analyte levels.
Question 7: Which specimen transport condition is required for an arterial blood gas (ABG) sample?
- Transported at room temperature within 30 minutes
- Placed in an ice slurry and analyzed within 30 minutes (Correct answer)
- Wrapped in foil to protect from light
- Stored at 37°C until analysis
Correct answer: Placed in an ice slurry and analyzed within 30 minutes
Ice slurry slows cellular metabolism in the sample, preventing changes in pH, PO2, and PCO2 before analysis.
PCT Lab Procedures 4
A PCT is about to perform venipuncture on a patient who has an IV infusing in the left arm.
What is the best action?