Phlebotomy Flashcards

Which tube should be drawn FIRST when collecting only a coagulation (PT/INR) specimen using a butterfly needle?

Answer: Draw a discard tube first, then fill the citrate tube

With a butterfly set, air in the tubing can underfill the first tube, so a discard tube ensures the citrate tube fills to the proper ratio.

What is the minimum waiting time after a patient has had an IV removed before drawing blood from that site?

Answer: At least 2–5 minutes

Waiting at least 2–5 minutes allows residual IV fluid to clear and ensures specimen integrity.

A phlebotomist notices the blood in the tube is hemolyzed. Which of the following is a common cause?

Answer: Mixing the tube too vigorously

Vigorous mixing or shaking of blood tubes causes mechanical destruction of red blood cells, resulting in hemolysis.

Which of the following analytes would be MOST affected by a hemolyzed specimen?

Answer: Potassium

Potassium is highly concentrated inside red blood cells, so hemolysis falsely elevates serum potassium levels.

When should a phlebotomist perform hand hygiene?

Answer: Before and after each patient contact

Standard precautions require hand hygiene both before and after patient contact to prevent cross-contamination.

A gray-top tube contains which anticoagulant/preservative combination?

Answer: Sodium fluoride and potassium oxalate

Gray-top tubes contain sodium fluoride (glycolysis inhibitor) and potassium oxalate (anticoagulant), used for glucose and lactate testing.

Which of the following best describes the purpose of the 'release tourniquet before needle withdrawal' step?

Answer: It reduces hematoma formation after needle removal

Releasing the tourniquet before withdrawing the needle prevents blood from being forced out of the puncture site, reducing hematoma risk.