CMLA Phlebotomy 5 — Questions and Answers
Question 1: Which complication is most likely if a phlebotomist accidentally punctures the brachial artery during venipuncture?
- Rapid, bright red blood flow and pulsation in the tube (Correct answer)
- Slow, dark blood flow with no pulsation
- Hemolysis of the specimen only
- No observable difference from venous blood
Correct answer: Rapid, bright red blood flow and pulsation in the tube
Arterial blood is oxygenated (bright red) and flows rapidly under higher pressure, often pulsating into the collection tube.
Question 2: The term 'sclerosed vein' refers to a vein that is:
- Hardened and fibrotic due to repeated venipuncture or disease (Correct answer)
- Collapsed from dehydration
- Fragile and prone to petechiae
- Distended from venous stasis
Correct answer: Hardened and fibrotic due to repeated venipuncture or disease
Sclerosed veins are stiff and cord-like from scar tissue, making successful venipuncture difficult and increasing the risk of hematoma.
Question 3: Why must the first few drops of blood be discarded when performing a capillary puncture for most tests?
- The first drops contain excess tissue fluid that can dilute and alter the specimen (Correct answer)
- The first drops are clotted
- The first drops contain higher glucose concentrations
- To clear the lancet device of debris
Correct answer: The first drops contain excess tissue fluid that can dilute and alter the specimen
The initial drops mix with interstitial fluid from tissue trauma, which can dilute analytes and affect test accuracy.
Question 4: Which gauge needle is most commonly used for routine adult venipuncture?
- 21 gauge (Correct answer)
- 25 gauge
- 18 gauge
- 23 gauge
Correct answer: 21 gauge
A 21-gauge needle provides adequate flow for evacuated tube collection without causing excessive hemolysis or vein trauma.
Question 5: A chain of custody procedure is required for specimens collected for:
- Forensic drug testing and legal/employment toxicology screens (Correct answer)
- Routine CBC and chemistry panels
- Blood bank crossmatch only
- Microbiology cultures only
Correct answer: Forensic drug testing and legal/employment toxicology screens
Chain of custody documents every person who handles a forensic specimen to ensure its integrity is legally defensible in court.
Question 6: What does the abbreviation 'SST' stand for, and what is its primary use?
- Serum Separator Tube; used for serum chemistry testing (Correct answer)
- Sterile Specimen Tube; used for microbiology
- Sodium Sulfate Tube; used for coagulation
- Slide Smear Tube; used for hematology
Correct answer: Serum Separator Tube; used for serum chemistry testing
The SST (gold or red-gray top) contains a clot activator and gel separator that separates serum from cells after centrifugation for chemistry testing.
Question 7: A phlebotomist is asked to collect a specimen from an arm with a peripherally inserted central catheter (PICC). What is the correct action?
- Collect from the opposite arm unless specifically ordered to draw from the line by nursing staff (Correct answer)
- Draw directly from the PICC line without consulting nursing
- Apply the tourniquet above the PICC and draw below it
- Refuse to draw from that patient entirely
Correct answer: Collect from the opposite arm unless specifically ordered to draw from the line by nursing staff
PICC lines are typically managed by nursing; phlebotomists should use the opposite arm unless specifically ordered and trained to access the line.
CMLA Phlebotomy 5
Which complication is most likely if a phlebotomist accidentally punctures the brachial artery during venipuncture?