Certified Phlebotomy Technician Exam Specimen Handling and Processing 4 — Questions and Answers
Question 1: Which of the following tests would be MOST affected by leaving a specimen in contact with cells for an extended time before centrifugation?
- Serum sodium
- Serum potassium (Correct answer)
- Serum albumin
- Serum total protein
Correct answer: Serum potassium
Potassium leaks from red blood cells over time, causing falsely elevated serum potassium levels if the specimen is not centrifuged promptly.
Question 2: A plasma separator tube (PST) contains which anticoagulant?
- Sodium citrate
- EDTA
- Lithium heparin (Correct answer)
- Potassium oxalate
Correct answer: Lithium heparin
Plasma separator tubes (light green-top) contain lithium heparin as the anticoagulant along with a gel separator to isolate plasma.
Question 3: What is the correct ratio of blood to anticoagulant in a sodium citrate tube for coagulation testing?
- 1:1
- 1:9
- 9:1 (Correct answer)
- 4:1
Correct answer: 9:1
Sodium citrate tubes require a 9:1 ratio of blood to anticoagulant (9 parts blood to 1 part citrate) to ensure accurate coagulation results.
Question 4: When should a phlebotomist recollect a specimen without consulting the laboratory?
- When the specimen is slightly hemolyzed
- When the patient is on anticoagulant therapy
- When the tube was not filled to the correct volume for a citrate tube (Correct answer)
- When the serum appears slightly icteric
Correct answer: When the tube was not filled to the correct volume for a citrate tube
A sodium citrate tube that is underfilled must be recollected because the incorrect blood-to-anticoagulant ratio will invalidate coagulation test results.
Question 5: Which of the following best describes 'lipemia' as a specimen quality issue?
- Presence of excess bilirubin causing yellow discoloration
- Presence of excess lipids causing a milky or turbid appearance (Correct answer)
- Presence of hemoglobin causing pink discoloration
- Presence of bacteria causing cloudiness
Correct answer: Presence of excess lipids causing a milky or turbid appearance
Lipemia refers to high lipid concentration in serum/plasma, causing a milky turbid appearance that can interfere with spectrophotometric assays.
Question 6: A blood culture specimen should be inoculated in which order?
- Aerobic bottle first, then anaerobic (Correct answer)
- Anaerobic bottle first, then aerobic
- Either order is acceptable
- Only one bottle is needed per draw
Correct answer: Aerobic bottle first, then anaerobic
When collecting blood cultures via syringe, the aerobic bottle is inoculated first to prevent air from the syringe from entering the anaerobic bottle and inhibiting anaerobic organism growth.
Question 7: Specimens for cold agglutinin testing must be transported at which temperature?
- On ice at 4°C
- Frozen at -20°C
- Body temperature at 37°C (Correct answer)
- Room temperature at 22°C
Correct answer: Body temperature at 37°C
Cold agglutinin specimens must be kept at 37°C during transport because cold temperatures cause the antibodies to agglutinate RBCs in the tube, giving false results.
Certified Phlebotomy Technician Exam Specimen Handling and Processing 4
Which of the following tests would be MOST affected by leaving a specimen in contact with cells for an extended time before centrifugation?