Equipment, Tubes, and Additives Flashcards

What is the function of sodium fluoride in a gray-top tube?

Answer: Inhibits glycolysis to preserve glucose levels

Sodium fluoride is a glycolytic inhibitor that prevents blood cells from consuming glucose, preserving accurate glucose levels in the specimen.

Which tube color contains the anticoagulant EDTA?

Answer: Lavender/purple

Lavender (purple) top tubes contain EDTA (ethylenediaminetetraacetic acid), which is the standard anticoagulant for hematology testing.

What is the purpose of a butterfly (winged infusion) needle set?

Answer: To access small or difficult veins with greater control

Butterfly needles have flexible tubing and a smaller needle, allowing better control and access to small, fragile, or rolling veins.

What does the thixotropic gel in a serum separator tube (SST) do during centrifugation?

Answer: Forms a barrier between serum and the cell clot

During centrifugation, the thixotropic gel migrates to the interface between the serum and the clot, forming a stable physical barrier that prevents mixing.

When using a syringe for blood collection, what is the correct method for transferring blood to evacuated tubes?

Answer: Attach a transfer device and allow the vacuum to pull blood in

A syringe transfer device is attached to replace the needle, and the tube's vacuum draws blood in, reducing hemolysis risk and preventing needle stick injuries.

What gauge needle is most commonly used for routine adult venipuncture?

Answer: 21-gauge

A 21-gauge needle is the standard for routine adult venipuncture, providing adequate blood flow while minimizing patient discomfort and hemolysis.