Certified Phlebotomy Technician Exam Specimen Collection 4 — Questions and Answers
Question 1: What is the primary purpose of inverting tubes gently after collection?
- To activate the clot faster
- To mix the additive uniformly with the blood specimen (Correct answer)
- To remove air bubbles
- To separate plasma from serum
Correct answer: To mix the additive uniformly with the blood specimen
Gentle inversion mixes the additive (anticoagulant, clot activator, etc.) thoroughly with the blood to ensure proper preservation.
Question 2: A requisition calls for a stat potassium level. The collected specimen is hemolyzed. What should the phlebotomist do?
- Report the result with a note that specimen was hemolyzed
- Centrifuge immediately to salvage the specimen
- Collect a new specimen and notify the nurse or ordering provider of the delay (Correct answer)
- Add saline to dilute the hemolysis
Correct answer: Collect a new specimen and notify the nurse or ordering provider of the delay
Hemolysis falsely elevates potassium (K+ leaks from cells), making the result unreliable; a new specimen must be collected.
Question 3: Which artery is most commonly used for arterial blood gas (ABG) collection?
- Brachial artery
- Femoral artery
- Radial artery (Correct answer)
- Ulnar artery
Correct answer: Radial artery
The radial artery at the wrist is the preferred ABG site because it is accessible, has collateral circulation, and is away from major nerves.
Question 4: What is the Allen test used for before an ABG draw?
- To locate the median cubital vein
- To confirm adequate collateral circulation in the hand before radial artery puncture (Correct answer)
- To test for latex allergy
- To assess pain tolerance
Correct answer: To confirm adequate collateral circulation in the hand before radial artery puncture
The Allen test compresses both radial and ulnar arteries to verify that the hand has adequate collateral blood flow before radial artery puncture.
Question 5: A 24-hour urine collection is ordered. Which instruction to the patient is CORRECT?
- Include the first morning void in the collection
- Discard the first morning void, then collect all urine for 24 hours ending with the next morning void (Correct answer)
- Collect only the final void of the day
- Refrigerate urine only if a preservative is not provided
Correct answer: Discard the first morning void, then collect all urine for 24 hours ending with the next morning void
The standard 24-hour protocol discards the first morning void to establish a start time, then collects all urine through and including the next morning void.
Question 6: Ammonia specimens must be transported in which manner?
- At room temperature in a brown bag
- Kept warm at 37°C
- On ice or in an ice-water slurry immediately after collection (Correct answer)
- Centrifuged before transport at room temperature
Correct answer: On ice or in an ice-water slurry immediately after collection
Ammonia is produced by red blood cells post-collection; chilling on ice slows this process and preserves accurate results.
Question 7: A patient has an IV running in the right antecubital vein. Where should the phlebotomist draw blood?
- From the IV catheter directly
- Above the IV site on the same arm
- From the left arm or a site below the IV on the same arm only if no other option exists (Correct answer)
- From any site on the right arm
Correct answer: From the left arm or a site below the IV on the same arm only if no other option exists
Drawing from the arm with an active IV risks dilution and contamination; use the opposite arm or, as a last resort, below the IV site on the same arm.
Certified Phlebotomy Technician Exam Specimen Collection 4
What is the primary purpose of inverting tubes gently after collection?