Venipuncture Procedures Flashcards

Which of the following lab tests would be MOST affected by prolonged tourniquet application?

Answer: Potassium

Potassium leaks from cells during venous stasis caused by prolonged tourniquet use, falsely elevating potassium levels (pseudohyperkalemia).

What is the PRIMARY reason to release the tourniquet before withdrawing the needle?

Answer: To prevent excessive bleeding and hematoma formation

Releasing the tourniquet before needle removal reduces venous back-pressure, minimizing the risk of hematoma at the puncture site.

A phlebotomist accidentally punctures through the back wall of a vein. What term describes this event?

Answer: Through-puncture

A through-puncture occurs when the needle passes entirely through both walls of the vein, causing blood to leak into surrounding tissue.

In the order of draw, which color tube should be collected IMMEDIATELY after the blood culture bottles?

Answer: Light blue (sodium citrate)

The light blue sodium citrate tube is the first additive tube collected after blood cultures to prevent contamination from other additives.

Which site should be AVOIDED for venipuncture due to the highest risk of nerve damage?

Answer: Basilic vein

The basilic vein lies close to the median nerve and brachial artery, making accidental nerve or arterial puncture more likely at this site.

What is the appropriate action if a patient's vein collapses during venipuncture with an evacuated tube?

Answer: Switch to a syringe or butterfly to reduce vacuum pressure

Switching to a syringe or butterfly set allows the phlebotomist to control suction manually, preventing vein collapse from excessive vacuum.

Which finding at the venipuncture site indicates accidental arterial puncture?

Answer: Bright red blood pulsating into the tube

Arterial blood is bright red and may enter the tube rapidly in a pulsatile manner due to the higher pressure in arteries.