ASPT Specimen Handling and Processing 5 — Questions and Answers
Question 1: What is the correct order of draw when collecting multiple tubes during a single venipuncture using evacuated tubes?
- EDTA, citrate, serum, heparin
- Citrate, serum/SST, heparin, EDTA (Correct answer)
- Serum, heparin, EDTA, citrate
- Heparin, EDTA, citrate, serum
Correct answer: Citrate, serum/SST, heparin, EDTA
The CLSI-recommended order is: blood cultures, citrate (blue), serum/SST (gold/red), heparin (green), EDTA (lavender), then other tubes.
Question 2: A 24-hour urine collection requires hydrochloric acid (HCl) as a preservative. What safety precaution must be followed?
- Add acid to the specimen after collection is complete
- Instruct the patient that acid is pre-added to the container (Correct answer)
- Store the container in the freezer throughout collection
- Collect the specimen without the preservative to avoid patient risk
Correct answer: Instruct the patient that acid is pre-added to the container
Acid preservatives are added to the container before the patient begins collection, and patients must be warned about the hazard of the chemical in their collection container.
Question 3: Which of the following best describes 'hemolysis' in a blood specimen?
- Clot formation in an anticoagulated tube
- Rupture of red blood cells releasing intracellular contents into plasma (Correct answer)
- Separation of plasma from cellular components
- Bacterial contamination of the specimen
Correct answer: Rupture of red blood cells releasing intracellular contents into plasma
Hemolysis occurs when red blood cell membranes rupture, releasing intracellular contents like potassium and hemoglobin into the surrounding plasma.
Question 4: What is the minimum volume of blood typically required to fill a blood culture bottle adequately?
- 1–2 mL
- 3–4 mL
- 8–10 mL (Correct answer)
- 15–20 mL
Correct answer: 8–10 mL
Standard blood culture bottles require 8–10 mL of blood per bottle to achieve the blood-to-broth ratio necessary for optimal organism recovery.
Question 5: When aliquoting a specimen, what is the most critical step to prevent specimen mix-up?
- Use color-coded aliquot tubes
- Label all aliquot tubes before transferring specimen (Correct answer)
- Complete one aliquot before starting the next
- Centrifuge all aliquots together
Correct answer: Label all aliquot tubes before transferring specimen
All aliquot tubes must be labeled with patient information before any specimen is transferred to prevent misidentification errors.
Question 6: Which of the following specimens requires immediate chilling in an ice slurry after collection?
- Serum for thyroid panel
- Whole blood for CBC
- Arterial blood gas (ABG) (Correct answer)
- Urine for urinalysis
Correct answer: Arterial blood gas (ABG)
ABG specimens must be chilled immediately in ice slurry to halt cellular metabolism and preserve the accurate measurement of blood gas values.
Question 7: What does a hemolysis index reported by the laboratory analyzer indicate to the phlebotomist?
- The specimen clotted before processing
- The degree of red blood cell lysis in the specimen (Correct answer)
- The lipid content of the specimen
- The volume of specimen collected
Correct answer: The degree of red blood cell lysis in the specimen
The hemolysis index quantifies free hemoglobin in the specimen, reflecting the degree of red blood cell rupture that occurred during or after collection.
ASPT Specimen Handling and Processing 5
What is the correct order of draw when collecting multiple tubes during a single venipuncture using evacuated tubes?