Phlebotomy Test Specimen Processing and Handling 3

Question 1

Which of the following best describes the correct technique for mixing an EDTA tube after venipuncture?

Accepted Answer

Gently invert 8–10 times

Answer

EDTA tubes should be gently inverted 8–10 times immediately after collection to ensure thorough anticoagulant mixing without causing hemolysis.

Question 2

Why must lithium heparin tubes NOT be used for lithium level tests?

Accepted Answer

The additive lithium will falsely elevate the patient's lithium result

Answer

The lithium in lithium heparin additive would be added to the patient's own lithium, causing a falsely elevated serum lithium measurement.

Question 3

A specimen tube that should be kept on ice during transport is a(n):

Accepted Answer

Arterial blood gas (ABG) syringe

Answer

ABG samples must be kept on ice to slow cellular metabolism and prevent gas exchange that would alter pH, pO₂, and pCO₂ values.

Question 4

What is the purpose of the separator gel found in SST (serum separator) tubes?

Accepted Answer

It forms a stable barrier between serum and clot after centrifugation

Answer

The polyethylene glycol gel migrates during centrifugation to form a physical barrier between the serum layer and the clot, preserving serum integrity.

Question 5

A 24-hour urine collection must be preserved with hydrochloric acid (HCl). Which test most commonly requires this preservative?

Accepted Answer

Urine catecholamines or metanephrines

Answer

Acid preservatives like HCl are required for 24-hour catecholamine and metanephrine collections to prevent oxidative breakdown of these compounds.

Phlebotomy Practice Test

Phlebotomy Practice Test

Phlebotomy Test Specimen Processing and Handling 3