PCT Phlebotomy 3 — Questions and Answers
Question 1: Hemolysis of a blood specimen can cause falsely ELEVATED results for which analyte?
- Sodium
- Potassium (Correct answer)
- Calcium
- Glucose
Correct answer: Potassium
Red blood cells contain high concentrations of potassium; cell lysis releases this intracellular potassium, falsely elevating serum levels.
Question 2: A patient on anticoagulant therapy has a hematoma forming at the venipuncture site. The PCT should:
- Continue drawing and apply pressure afterward
- Immediately remove the needle and apply firm pressure for at least 5 minutes (Correct answer)
- Apply a warm compress and continue the draw
- Document the hematoma and proceed with the draw
Correct answer: Immediately remove the needle and apply firm pressure for at least 5 minutes
Anticoagulated patients bleed more readily; prompt needle removal and extended pressure prevent serious hematoma expansion.
Question 3: Which capillary puncture site is preferred for infants under 1 year of age?
- Earlobe
- Index finger pad
- Heel (plantar surface) (Correct answer)
- Big toe
Correct answer: Heel (plantar surface)
Heel puncture on the plantar surface is the standard site for neonates and infants because finger bones are too close to the skin surface.
Question 4: The maximum depth for a heel stick in a neonate is:
- 1.0 mm
- 2.0 mm (Correct answer)
- 3.0 mm
- 4.0 mm
Correct answer: 2.0 mm
CLSI guidelines limit neonatal heel puncture depth to 2.0 mm to avoid hitting the calcaneus (heel bone) and causing osteomyelitis.
Question 5: Which tube is used for coagulation studies such as PT and aPTT?
- Lavender top (EDTA)
- Light blue top (sodium citrate) (Correct answer)
- Green top (heparin)
- Gray top (fluoride/oxalate)
Correct answer: Light blue top (sodium citrate)
Sodium citrate binds calcium to reversibly inhibit coagulation, preserving clotting factors for accurate coagulation testing.
Question 6: A phlebotomist notices the tube stopper color and the test requisition do not match. The BEST action is to:
- Use the tube available and note it on the label
- Draw with the available tube and centrifuge immediately
- Stop and clarify with the ordering nurse or provider before collecting (Correct answer)
- Collect the specimen and notify the lab after delivery
Correct answer: Stop and clarify with the ordering nurse or provider before collecting
Using the wrong additive tube can invalidate results or harm the patient; clarification before collection is always the safest step.
Question 7: Why is the first drop of blood from a capillary puncture discarded?
- It contains excess red blood cells
- It may be contaminated with tissue fluid that can dilute or alter results (Correct answer)
- It clots too quickly for testing
- It is required by OSHA regulations
Correct answer: It may be contaminated with tissue fluid that can dilute or alter results
The initial puncture causes tissue fluid to mix with blood, which can dilute the sample and skew analyte concentrations.
PCT Phlebotomy 3
Hemolysis of a blood specimen can cause falsely ELEVATED results for which analyte?