Phlebotomy Specimen Processing and Handling Questions and Answers 1 — Questions and Answers
Question 1: A phlebotomist has just drawn a serum separator tube (SST) for a chemistry panel. What is the correct minimum time the tube should be allowed to clot before centrifugation?
- 10 minutes
- 30 minutes (Correct answer)
- 60 minutes
- Immediately
Correct answer: 30 minutes
Serum separator tubes require adequate time for complete clot formation to ensure proper separation of serum from cellular components during centrifugation. The standard recommended minimum clotting time is 30 minutes at room temperature.
Question 2: Which of the following would be a valid reason for a laboratory to reject a blood specimen?
- The specimen was collected in a tube with an expired date. (Correct answer)
- The patient's name is written in pen on the label.
- The specimen was transported at room temperature.
- The phlebotomist's initials are on the label.
Correct answer: The specimen was collected in a tube with an expired date.
Laboratories have strict criteria for specimen acceptance to ensure test accuracy. Using an expired collection tube is a reason for rejection because the vacuum may be insufficient and the additives may have degraded, compromising the specimen's integrity.
Question 3: A test for bilirubin levels has been ordered. What is the most critical handling requirement for this specimen immediately after collection?
- Place the tube in an ice slurry.
- Keep the tube at body temperature (37°C).
- Protect the tube from light. (Correct answer)
- Centrifuge the tube immediately.
Correct answer: Protect the tube from light.
Bilirubin is a photosensitive analyte, meaning it breaks down when exposed to light. To ensure accurate test results, the specimen must be protected from light by wrapping it in aluminum foil or placing it in an amber-colored tube immediately after collection.
Question 4: A phlebotomist must prepare a specimen for transport to a reference lab that requires chilled handling. What is the proper technique for chilling the specimen?
- Placing the tube directly on a large block of ice.
- Submerging the tube in a mixture of crushed ice and water. (Correct answer)
- Storing the tube in the refrigerator for 30 minutes before transport.
- Attaching a cold pack to the outside of the transport bag.
Correct answer: Submerging the tube in a mixture of crushed ice and water.
For proper chilling, the specimen tube must be fully surrounded by the cooling medium to ensure rapid and consistent temperature reduction. A slurry of crushed ice and water provides the most effective contact with the entire surface of the tube.
Question 5: When balancing a centrifuge for spinning blood tubes, which principle must be followed?
- Tubes of the same size and fill volume must be placed directly opposite each other. (Correct answer)
- Heavier tubes should be placed closer to the center of the rotor.
- All available slots in the centrifuge must be filled before operation.
- Plasma tubes and serum tubes should never be centrifuged at the same time.
Correct answer: Tubes of the same size and fill volume must be placed directly opposite each other.
To prevent damage to the centrifuge and ensure proper specimen separation, the rotor must be balanced. This is achieved by placing tubes of equal size, shape, and volume in opposite positions to distribute the weight evenly.
Question 6: A phlebotomist is collecting a specimen for a legal blood alcohol level test. Which of the following is a key component of the 'chain of custody' process for this specimen?
- Using a larger gauge needle for the collection.
- Having the patient sign a waiver before the draw.
- Documenting every person who handles the specimen. (Correct answer)
- Drawing a discard tube before the required gray-top tube.
Correct answer: Documenting every person who handles the specimen.
Chain of custody is a legal and procedural process that tracks a specimen from the moment of collection to its final disposition. It requires meticulous documentation of everyone who handles the specimen to ensure its integrity for legal proceedings.
Phlebotomy Specimen Processing and Handling Questions and Answers 1
A phlebotomist has just drawn a serum separator tube (SST) for a chemistry panel.
What is the correct minimum time the tube should be allowed to clot before centrifugation?