Phlebotomy Test Special Collection Procedures 2 — Questions and Answers
Question 1: When collecting a neonatal bilirubin specimen, what is the primary concern regarding light exposure?
- Light degrades bilirubin, causing falsely low results (Correct answer)
- Light increases bilirubin concentration
- Light causes hemolysis of the specimen
- Light promotes bacterial growth in the tube
Correct answer: Light degrades bilirubin, causing falsely low results
Bilirubin is photosensitive and breaks down rapidly when exposed to light, so specimens must be wrapped in foil or collected in amber tubes immediately.
Question 2: A glucose tolerance test (GTT) requires the patient to fast for how long before the baseline draw?
- 4 hours
- 8–12 hours (Correct answer)
- 2 hours
- 24 hours
Correct answer: 8–12 hours
Standard GTT protocol requires an 8–12 hour fast to establish a reliable fasting baseline glucose level.
Question 3: Which needle gauge is most appropriate for a blood culture collection to minimize contamination risk while maintaining adequate flow?
- 18 gauge
- 21–22 gauge (Correct answer)
- 25 gauge
- 16 gauge
Correct answer: 21–22 gauge
A 21–22 gauge needle provides adequate flow for blood culture volumes while reducing hemolysis and patient discomfort.
Question 4: When performing a capillary blood gas collection from a neonate's heel, what must be done to the heel before puncture?
- Warm the heel to 42°C (107.6°F) for at least 3–5 minutes (Correct answer)
- Apply ice to constrict capillaries
- Clean with povidone-iodine only
- Apply a tourniquet above the ankle
Correct answer: Warm the heel to 42°C (107.6°F) for at least 3–5 minutes
Warming arterializes the capillary blood by causing vasodilation, which improves the accuracy of blood gas values.
Question 5: For a therapeutic drug monitoring (TDM) trough level, blood should be drawn at which time?
- 30 minutes after drug administration
- Immediately before the next scheduled dose (Correct answer)
- 2 hours after drug administration
- At any time during the dosing interval
Correct answer: Immediately before the next scheduled dose
Trough levels are drawn immediately before the next dose to capture the lowest drug concentration in the bloodstream.
Question 6: Which collection method is used to diagnose malaria by examining thick and thin blood smears?
- Venipuncture into an EDTA tube only
- Fingerstick or venipuncture with smears made immediately (Correct answer)
- Arterial puncture into a heparinized syringe
- Urine midstream catch
Correct answer: Fingerstick or venipuncture with smears made immediately
Fresh blood smears—thick for parasite detection and thin for species identification—can be made from either a fingerstick or venipuncture collected in EDTA.
Question 7: A STAT arterial blood gas (ABG) sample collected in a heparinized syringe must be transported to the lab within what time frame if kept at room temperature?
- 60 minutes
- 30 minutes (Correct answer)
- 4 hours
- 15 minutes
Correct answer: 30 minutes
ABG samples must reach the analyzer within 30 minutes at room temperature to prevent continued cellular metabolism from altering pH, PO2, and PCO2 values.
Phlebotomy Test Special Collection Procedures 2
When collecting a neonatal bilirubin specimen, what is the primary concern regarding light exposure?