Certified Phlebotomy Technician Exam Equipment and Supplies 1 — Questions and Answers
Question 1: Which needle gauge is most commonly used for routine venipuncture in adults?
- 16 gauge
- 21 gauge (Correct answer)
- 25 gauge
- 30 gauge
Correct answer: 21 gauge
A 21-gauge needle is the standard choice for routine adult venipuncture, balancing flow rate and vein trauma.
Question 2: What is the primary purpose of the evacuated tube system (ETS) in phlebotomy?
- To sterilize the collection site
- To create a vacuum that draws blood directly into the tube (Correct answer)
- To mix anticoagulants before collection
- To warm the blood sample
Correct answer: To create a vacuum that draws blood directly into the tube
The evacuated tube system uses a pre-measured vacuum to draw a precise volume of blood directly into the collection tube.
Question 3: Which additive is found in a light blue (sodium citrate) tube?
- EDTA
- Heparin
- Sodium citrate (Correct answer)
- Potassium oxalate
Correct answer: Sodium citrate
Light blue-topped tubes contain sodium citrate, which is used for coagulation studies by chelating calcium ions.
Question 4: What is the correct blood-to-additive ratio required for a sodium citrate (light blue) tube?
- 1:1
- 9:1 (Correct answer)
- 4:1
- 2:1
Correct answer: 9:1
Light blue tubes require a 9:1 blood-to-sodium-citrate ratio; underfilling invalidates coagulation test results.
Question 5: A butterfly needle is most appropriate for which situation?
- Large antecubital veins in adults
- Small or fragile veins and pediatric patients (Correct answer)
- Arterial blood gas collection only
- Central line draws
Correct answer: Small or fragile veins and pediatric patients
Butterfly (winged infusion) needles are designed for small, fragile, or difficult veins, including those in children and elderly patients.
Question 6: What color tube top indicates a serum separator tube (SST) with a clot activator?
- Lavender
- Green
- Gold or red-gray (Correct answer)
- Royal blue
Correct answer: Gold or red-gray
Gold or red-gray (tiger-top) tubes contain a clot activator and gel separator for serum chemistry tests.
Certified Phlebotomy Technician Exam Equipment and Supplies 1
Which needle gauge is most commonly used for routine venipuncture in adults?