Nokea
You should avoid which of the following actions that can cause hemolysis?
- A. Using a 20- or 22-gauge needle and syringe
- B. Leaving the tourniquet on longer than 1 minute
- C. Using an evacuated tube set and a 25-gauge needle
- D. Withdrawing the blood slowly when using a needle and syringe
Correct Answer: B,C
Rationale: Leaving the tourniquet on too long or using a small-gauge needle (e.g., 25-gauge) with an evacuated tube can cause hemolysis due to excessive pressure or shear stress on red blood cells.
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There are several tips you may use to find a suitable vein for venipuncture. Which of the following techniques is inappropriate?
- A. Have the patient hang the proposed arm dependently to allow blood to better fill the veins of the arm.
- B. Use an alcohol swab to apply rubbing friction in an attempt to stimulate the vein to distend.
- C. Using your fingers, slap the skin over the vein in an attempt to stimulate the vein to distend.
- D. Apply a warm pack to the site for 5 to 10 minutes to dilate the vein.
Correct Answer: C
Rationale: Slapping the skin is inappropriate as it may cause discomfort or bruising and is not a standard technique for vein distension.
What color tubes will you need for these tests?
- A. Red
- B. Gray
- C. Light blue
- D. Yellow
- E. Lavender
- F. Green
Correct Answer: D,E,F
Rationale: Blood cultures use yellow tubes, complete blood count uses lavender, electrolytes use green, and glucose uses gray (though red is sometimes used for chemistry tests, green is standard for electrolytes).
You are performing phlebotomy on an elderly patient using a needle and syringe setup. Besides hemolysis, what can happen if you pull the plunger back too rapidly?
- A. Vein collapse
- B. Excessive bleeding
- C. Needle dislodgement
- D. Pain or discomfort
Correct Answer: A
Rationale: Pulling the plunger back too rapidly can create excessive negative pressure, causing the vein to collapse, especially in elderly patients with fragile veins.
In what sequence will you draw the colored tubes?
- A. Yellow
- B. Lavender
- C. Green
- D. Gray
Correct Answer: A,B,C,D
Rationale: The order of draw is yellow (blood cultures) first to prevent contamination, followed by lavender (CBC), green (electrolytes), and gray (glucose) to minimize additive carryover.
Which one of the following statements is not accurate when describing veins and arteries?
- A. Veins have valves; arteries do not.
- B. Valves control the direction of blood flow in veins.
- C. Arteries have higher blood pressure than veins.
- D. Veins have thicker walls than arteries.
- E. Veins must fight against gravity to return blood to the heart.
Correct Answer: D
Rationale: Veins have thinner walls than arteries, which have thicker walls to withstand higher blood pressure.