Certified Phlebotomy Technician Exam Specimen Collection 2 — Questions and Answers
Question 1: Which gauge needle is most commonly used for routine venipuncture in adults?
- 16 gauge
- 18 gauge
- 21 gauge (Correct answer)
- 25 gauge
Correct answer: 21 gauge
A 21-gauge needle is the standard choice for routine adult venipuncture, balancing flow rate and patient comfort.
Question 2: What is the maximum time a tourniquet should remain applied before venipuncture to avoid hemoconcentration?
- 30 seconds
- 1 minute (Correct answer)
- 2 minutes
- 5 minutes
Correct answer: 1 minute
A tourniquet should not be applied for more than 1 minute before puncture to prevent hemoconcentration and altered test results.
Question 3: Which blood culture collection technique helps prevent contamination?
- Collecting from an existing IV line
- Cleansing the site with 70% isopropyl alcohol only
- Using chlorhexidine or iodine after alcohol and allowing it to dry (Correct answer)
- Drawing from the antecubital fossa without skin prep
Correct answer: Using chlorhexidine or iodine after alcohol and allowing it to dry
Blood culture sites require a two-step antiseptic prep (alcohol followed by chlorhexidine or iodine, fully dried) to minimize contamination.
Question 4: When collecting capillary blood from a neonate's heel, which area should be avoided?
- Lateral plantar surface
- Medial plantar surface
- Central posterior curvature of the heel (Correct answer)
- Lateral heel
Correct answer: Central posterior curvature of the heel
The central posterior curvature of the heel is avoided in neonates because it overlies the calcaneus bone and risks osteomyelitis.
Question 5: A patient's arm shows petechiae after tourniquet application. What does this indicate?
- Normal response to pressure
- Possible coagulation or platelet disorder (Correct answer)
- Tourniquet too loose
- Vein collapsed
Correct answer: Possible coagulation or platelet disorder
Petechiae (small red dots) appearing after tourniquet use suggest a possible coagulation defect or thrombocytopenia.
Question 6: Which additive is found in a light blue (sodium citrate) tube and why is underfilling critical?
- EDTA; affects cell morphology
- Sodium citrate; incorrect blood-to-anticoagulant ratio affects coagulation results (Correct answer)
- Heparin; causes clotting
- SST gel; disrupts fibrin formation
Correct answer: Sodium citrate; incorrect blood-to-anticoagulant ratio affects coagulation results
Light blue tubes use sodium citrate at a precise 9:1 blood-to-anticoagulant ratio; underfilling dilutes the specimen and falsely prolongs PT/aPTT.
Question 7: What is the preferred site for venipuncture in an infant under 2 years old?
- Antecubital fossa
- Dorsal hand veins
- Heel capillary stick (Correct answer)
- Femoral vein
Correct answer: Heel capillary stick
Heel capillary puncture (heel stick) is the preferred method for infants under 2 years due to vein size and safety concerns.
Certified Phlebotomy Technician Exam Specimen Collection 2
Which gauge needle is most commonly used for routine venipuncture in adults?