NRCMA Phlebotomy 3 — Questions and Answers
Question 1: Which tube should be drawn FIRST when collecting only a coagulation (PT/INR) specimen using a butterfly needle?
- Directly fill the citrate tube
- Draw a discard tube first, then fill the citrate tube (Correct answer)
- Fill the SST tube first, then the citrate tube
- Draw blood into a green-top tube first
Correct 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.
Question 2: What is the minimum waiting time after a patient has had an IV removed before drawing blood from that site?
- No waiting required
- 2 minutes
- At least 2–5 minutes (Correct answer)
- 30 minutes
Correct answer: At least 2–5 minutes
Waiting at least 2–5 minutes allows residual IV fluid to clear and ensures specimen integrity.
Question 3: A phlebotomist notices the blood in the tube is hemolyzed. Which of the following is a common cause?
- Using too large a needle gauge
- Mixing the tube too vigorously (Correct answer)
- Leaving the tourniquet on for less than 1 minute
- Collecting blood in a pre-chilled tube
Correct answer: Mixing the tube too vigorously
Vigorous mixing or shaking of blood tubes causes mechanical destruction of red blood cells, resulting in hemolysis.
Question 4: Which of the following analytes would be MOST affected by a hemolyzed specimen?
- Sodium
- Potassium (Correct answer)
- Blood glucose
- Creatinine
Correct answer: Potassium
Potassium is highly concentrated inside red blood cells, so hemolysis falsely elevates serum potassium levels.
Question 5: When should a phlebotomist perform hand hygiene?
- Only before the procedure
- Only after the procedure
- Before and after each patient contact (Correct answer)
- Only when hands are visibly soiled
Correct answer: Before and after each patient contact
Standard precautions require hand hygiene both before and after patient contact to prevent cross-contamination.
Question 6: A gray-top tube contains which anticoagulant/preservative combination?
- Sodium citrate and thrombin
- Sodium fluoride and potassium oxalate (Correct answer)
- EDTA and gel separator
- Lithium heparin and ammonium heparin
Correct answer: Sodium fluoride and potassium oxalate
Gray-top tubes contain sodium fluoride (glycolysis inhibitor) and potassium oxalate (anticoagulant), used for glucose and lactate testing.
Question 7: Which of the following best describes the purpose of the 'release tourniquet before needle withdrawal' step?
- It prevents vein collapse during collection
- It reduces hematoma formation after needle removal (Correct answer)
- It increases blood flow to fill the tube faster
- It sterilizes the puncture site
Correct 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.
NRCMA Phlebotomy 3
Which tube should be drawn FIRST when collecting only a coagulation (PT/INR) specimen using a butterfly needle?