CMLA Phlebotomy 2 — Questions and Answers
Question 1: Which additive is found in a royal blue-top tube used for trace element testing?
- EDTA or no additive (trace-metal free) (Correct answer)
- Sodium citrate
- Lithium heparin
- Sodium fluoride
Correct answer: EDTA or no additive (trace-metal free)
Royal blue-top tubes are trace-metal free and may contain EDTA, heparin, or no additive depending on the test required.
Question 2: A patient has a hematoma at a previous venipuncture site. Where should the phlebotomist collect the next specimen?
- A different site, avoiding the hematoma (Correct answer)
- Directly through the center of the hematoma
- Distal to the hematoma on the same vein
- The same site after applying heat
Correct answer: A different site, avoiding the hematoma
A hematoma indicates extravasation of blood and can contaminate the specimen, so an alternate site must be selected.
Question 3: What is the correct angle of needle insertion for a standard venipuncture?
- 15–30 degrees (Correct answer)
- 45–60 degrees
- 5–10 degrees
- 60–75 degrees
Correct answer: 15–30 degrees
A 15–30 degree angle allows the needle to enter the vein without going through the posterior wall.
Question 4: Which tube is used to collect a specimen for a prothrombin time (PT) test?
- Light blue (sodium citrate) (Correct answer)
- Red (no additive)
- Lavender (EDTA)
- Green (heparin)
Correct answer: Light blue (sodium citrate)
The light blue tube contains sodium citrate, which preserves clotting factors for coagulation studies like PT and aPTT.
Question 5: When performing a capillary puncture on an infant, which site is preferred?
- Lateral or medial plantar surface of the heel (Correct answer)
- Fingertip of the index finger
- Earlobe
- Big toe
Correct answer: Lateral or medial plantar surface of the heel
The heel is the preferred site for infant capillary puncture to avoid injury to bone, nerves, and tendons.
Question 6: Which of the following would cause a falsely elevated potassium level in a serum specimen?
- Hemolysis of red blood cells (Correct answer)
- Icterus (jaundice)
- Lipemia
- Prolonged refrigeration
Correct answer: Hemolysis of red blood cells
Hemolyzed RBCs release intracellular potassium into the serum, falsely elevating potassium results.
Question 7: The order of draw for a lavender-top tube in a multi-tube venipuncture is:
- After red/gold and green tubes (Correct answer)
- First, before all other tubes
- Immediately after light blue
- Last, after yellow (SPS)
Correct answer: After red/gold and green tubes
EDTA tubes (lavender) are drawn after serum and heparin tubes to prevent EDTA carryover from affecting clotting or chemistry results.
CMLA Phlebotomy 2
Which additive is found in a royal blue-top tube used for trace element testing?