ASPT Blood Collection Equipment & Supplies 1 — Questions and Answers
Question 1: Which tube color indicates the presence of EDTA as an additive?
- Red
- Lavender/Purple (Correct answer)
- Green
- Yellow
Correct answer: Lavender/Purple
Lavender/purple-top tubes contain EDTA (ethylenediaminetetraacetic acid), an anticoagulant used for hematology tests such as the CBC.
Question 2: What is the primary purpose of yellow-top tubes containing sodium polyanethol sulfonate (SPS)?
- Coagulation studies
- Blood cultures (Correct answer)
- Serum chemistry panels
- Whole blood glucose testing
Correct answer: Blood cultures
Yellow SPS tubes are used for blood culture collections because SPS inhibits complement, phagocytosis, and certain antibiotics that could interfere with microbial growth.
Question 3: Which needle gauge is most commonly used for routine adult venipuncture?
- 16–18 gauge
- 20–21 gauge (Correct answer)
- 23–25 gauge
- 27–30 gauge
Correct answer: 20–21 gauge
20–21 gauge needles are standard for routine adult venipuncture, providing adequate blood flow while minimizing patient discomfort and hemolysis.
Question 4: The green-top tube contains which anticoagulant?
- Sodium citrate
- EDTA
- Heparin (Correct answer)
- Potassium oxalate
Correct answer: Heparin
Green-top tubes contain heparin (sodium, lithium, or ammonium form), which prevents clotting by inhibiting thrombin activity.
Question 5: How many times should an EDTA tube be inverted after blood collection to ensure proper mixing?
- 2–3 times
- 5–6 times
- 8–10 times (Correct answer)
- 12–15 times
Correct answer: 8–10 times
EDTA tubes should be inverted 8–10 times to ensure complete mixing of the anticoagulant with the blood and prevent microclot formation.
Question 6: Which collection device is BEST suited for patients with fragile, small, or difficult veins?
- Straight needle with evacuated tube holder
- Butterfly (winged infusion) set (Correct answer)
- 18-gauge needle with syringe
- Lancet device
Correct answer: Butterfly (winged infusion) set
Butterfly (winged infusion) sets allow more flexible positioning, a shallower insertion angle, and gentler blood collection, making them ideal for fragile or difficult veins.
Question 7: Which tube color is used for prothrombin time (PT) and partial thromboplastin time (PTT) testing?
- Lavender
- Green
- Light blue (Correct answer)
- Gold/SST
Correct answer: Light blue
Light blue-top tubes contain sodium citrate at a 9:1 blood-to-additive ratio, which is required for accurate coagulation studies including PT and PTT.
ASPT Blood Collection Equipment & Supplies 1
Which tube color indicates the presence of EDTA as an additive?