AMCA Phlebotomy and Blood Collection 4 — Questions and Answers
Question 1: A patient has small, fragile veins. Which needle gauge is most appropriate for venipuncture?
- 16 gauge
- 18 gauge
- 21 gauge
- 23 gauge (Correct answer)
Correct answer: 23 gauge
A 23-gauge needle is smaller and causes less trauma, making it ideal for patients with small or fragile veins.
Question 2: Which condition can cause falsely elevated potassium levels in a blood specimen?
- Hemolysis (Correct answer)
- Lipemia
- Icterus
- Turbidity
Correct answer: Hemolysis
Hemolysis releases intracellular potassium from red blood cells into the serum, causing falsely elevated potassium results.
Question 3: When performing a capillary puncture on an infant, the preferred site is:
- The earlobe
- The fingertip
- The medial or lateral plantar heel surface (Correct answer)
- The big toe
Correct answer: The medial or lateral plantar heel surface
The medial or lateral plantar surface of the heel is the recommended capillary puncture site for infants to avoid injury to nerves and bone.
Question 4: Which additive in a blood collection tube inhibits thrombin and is used for coagulation studies?
- EDTA
- Sodium citrate (Correct answer)
- Sodium fluoride
- Lithium heparin
Correct answer: Sodium citrate
Sodium citrate chelates calcium to inhibit the coagulation cascade and is the required anticoagulant for coagulation (PT/aPTT) testing.
Question 5: A phlebotomist notices petechiae on a patient's arm after releasing the tourniquet. This finding most likely indicates:
- An allergic reaction to the tourniquet
- Fragile capillaries or a coagulation disorder (Correct answer)
- Infection at the venipuncture site
- Improper tourniquet removal technique
Correct answer: Fragile capillaries or a coagulation disorder
Petechiae are pinpoint hemorrhages that suggest fragile capillaries or an underlying coagulation or platelet disorder.
Question 6: The maximum time a tourniquet should remain applied before venipuncture to prevent hemoconcentration is:
- 30 seconds
- 1 minute (Correct answer)
- 2 minutes
- 3 minutes
Correct answer: 1 minute
Tourniquets should not remain in place longer than 1 minute to prevent hemoconcentration and falsely elevated analyte levels.
Question 7: Which of the following tests requires a chain-of-custody procedure during specimen collection?
- Complete blood count (CBC)
- Basic metabolic panel
- Forensic drug screening (Correct answer)
- Prothrombin time (PT)
Correct answer: Forensic drug screening
Forensic drug screening requires a documented chain of custody to ensure specimen integrity and legal admissibility.
AMCA Phlebotomy and Blood Collection 4
A patient has small, fragile veins.
Which needle gauge is most appropriate for venipuncture?