Venipuncture and Phlebotomy Flashcards

Which gray top tube additive both prevents clotting and preserves glucose?

Answer: Sodium fluoride and potassium oxalate

Gray top tubes contain sodium fluoride to inhibit glycolysis and potassium oxalate as an anticoagulant.

What is the purpose of the gel in a serum separator tube (SST, gold/red-gray top)?

Answer: To separate serum from cells after centrifugation

The thixotropic gel forms a barrier between serum and cells when spun, allowing clean serum separation.

Why must a clot activator (red or SST) tube be allowed to clot before centrifugation?

Answer: To ensure complete serum separation and avoid fibrin

Allowing full clotting (usually 30 minutes) ensures clean serum and prevents fibrin clots during testing.

Which nerve is at greatest risk of injury when the basilic vein is used for venipuncture?

Answer: Median nerve

The basilic vein lies near the median nerve and brachial artery, increasing injury risk, so it is a last choice.

What is the correct procedure for handling a needlestick injury to the phlebotomist?

Answer: Wash the site, report it, and seek medical evaluation

Immediate washing, reporting, and medical evaluation follow exposure-control protocol to manage infection risk.

How should used needles be disposed of immediately after a draw?

Answer: Activate the safety device and place in a sharps container

Engaging the safety mechanism and discarding in a puncture-proof sharps container prevents needlestick injuries.

Which patient position is safest for any blood draw to reduce injury if fainting occurs?

Answer: Seated in a chair with armrest or lying down

A seated chair with armrests or a reclined position protects the patient from falling if syncope occurs.