Certified Phlebotomy Technician Specimen Handling and Processing Questions and Answers — Questions and Answers
Question 1: A phlebotomist is preparing to collect a blood specimen for an ammonia level. Which of the following handling procedures is critical for ensuring the accuracy of the test result?
- The specimen must be protected from light by wrapping it in foil.
- The specimen must be kept at body temperature (37°C) until centrifugation.
- The specimen must be placed in an ice slurry immediately after collection. (Correct answer)
- The specimen must be allowed to clot for at least 60 minutes before processing.
Correct answer: The specimen must be placed in an ice slurry immediately after collection.
Ammonia levels in a blood specimen increase rapidly at room temperature. Chilling the specimen immediately in an ice slurry slows down the metabolic processes that lead to this increase, ensuring an accurate measurement.
Question 2: Which of the following analytes requires the blood collection tube to be protected from light as soon as it is drawn?
- Glucose
- Bilirubin (Correct answer)
- Potassium
- Lactic Acid
Correct answer: Bilirubin
Bilirubin is a light-sensitive analyte. Exposure to light, especially direct sunlight or fluorescent light, can cause it to break down, leading to falsely low test results. Therefore, the tube must be protected, often by wrapping it in aluminum foil or using an amber-colored tube.
Question 3: A phlebotomist receives an order to draw blood for a cold agglutinin test. What is the correct handling procedure for this specimen immediately following collection?
- Place the tube in a 37°C heat block or incubator. (Correct answer)
- Immediately centrifuge the specimen at high speed.
- Submerge the tube in an ice-water bath.
- Gently invert the tube 15-20 times.
Correct answer: Place the tube in a 37°C heat block or incubator.
Cold agglutinins are antibodies that cause red blood cells to clump together at temperatures below body temperature. To prevent this from happening, which would interfere with the test, the specimen must be kept warm (at 37°C) until the serum can be separated from the cells.
Question 4: According to CLSI guidelines, what is the maximum amount of time that should elapse between the collection of a routine blood specimen for serum testing and the separation of serum from the cells by centrifugation?
- 30 minutes
- 4 hours
- 2 hours (Correct answer)
- 8 hours
Correct answer: 2 hours
For most routine chemistry tests, serum or plasma should be separated from the cells within two hours of collection to prevent metabolic changes in the cells from altering the composition of the serum/plasma, which can lead to inaccurate results.
Question 5: A laboratory rejects a light blue top tube for a coagulation test. Which of the following is the most likely reason for specimen rejection?
- The tube was not protected from light.
- The tube was only filled to 75% capacity. (Correct answer)
- The tube was inverted 8 times after collection.
- The tube was transported at room temperature.
Correct answer: The tube was only filled to 75% capacity.
Coagulation testing requires a specific ratio of blood to anticoagulant (9:1). An underfilled tube (short draw) will have an incorrect ratio, with too much anticoagulant, which will lead to inaccurate and prolonged clotting times. Most tubes have an indicator mark and must be filled to ±10% of that volume.
Question 6: A phlebotomist is sending a frozen plasma specimen to a reference laboratory. Which of the following is the correct procedure for transport?
- Place the original glass collection tube in a biohazard bag with a frozen gel pack.
- Transport the separated plasma in a plastic screw-cap vial on dry ice.
- Ship the unspun whole blood tube in a refrigerated container. (Correct answer)
- Wrap the frozen plasma tube in foil and place it in a standard mailer.
Correct answer: Ship the unspun whole blood tube in a refrigerated container.
Frozen specimens must be maintained in a frozen state during transport. This is typically achieved by shipping the separated plasma, which should be in a plastic transport vial to prevent breakage, on dry ice. Glass tubes can break when frozen.
Certified Phlebotomy Technician Specimen Handling and Processing Questions and Answers
A phlebotomist is preparing to collect a blood specimen for an ammonia level.
Which of the following handling procedures is critical for ensuring the accuracy of the test result?