CMA Clinical Procedures and Specimen Handling 3 — Questions and Answers
Question 1: A hemolyzed blood specimen is most likely caused by:
- Using a large-bore needle
- Drawing blood too slowly through a small-gauge needle (Correct answer)
- Inverting the tube gently after collection
- Storing the specimen at room temperature
Correct answer: Drawing blood too slowly through a small-gauge needle
Forcing blood through a small-gauge needle creates shear stress that ruptures red blood cells, causing hemolysis.
Question 2: Which tube additive is found in a light-blue-topped vacutainer tube used for coagulation studies?
- EDTA
- Sodium citrate (Correct answer)
- Lithium heparin
- Sodium fluoride
Correct answer: Sodium citrate
Light-blue tops contain sodium citrate, which chelates calcium to prevent clotting for coagulation tests like PT and PTT.
Question 3: When performing an intradermal injection for a tuberculin skin test (TST), the correct angle of insertion is:
- 90 degrees
- 45 degrees
- 15 degrees (Correct answer)
- 30 degrees
Correct answer: 15 degrees
Intradermal injections are administered at a 10-15 degree angle to deposit the solution within the dermis, forming a wheal.
Question 4: A patient's urine specific gravity is 1.035. This finding most likely indicates:
- Adequate hydration
- Overhydration
- Dehydration or highly concentrated urine (Correct answer)
- Dilute urine from excessive fluid intake
Correct answer: Dehydration or highly concentrated urine
Normal specific gravity is 1.001-1.030; a value of 1.035 indicates highly concentrated urine, suggestive of dehydration.
Question 5: When collecting a stool specimen for occult blood testing, the patient should avoid which food for 3 days prior?
- White rice
- Red meat (Correct answer)
- Yogurt
- Apples
Correct answer: Red meat
Red meat contains hemoglobin that can cause false-positive results on guaiac-based fecal occult blood tests.
Question 6: Which personal protective equipment (PPE) is required when handling all laboratory specimens?
- Gown and face shield only
- Gloves only
- Gloves and face protection as appropriate (Correct answer)
- N95 respirator and gloves
Correct answer: Gloves and face protection as appropriate
Standard precautions require gloves for all specimen handling, with additional PPE (face protection, gown) based on anticipated splash risk.
Question 7: The bevel of the needle should be positioned facing up during venipuncture because:
- It prevents the needle from slipping out of the vein
- It allows the needle to enter the vein more smoothly and reduces trauma (Correct answer)
- It seals the needle tip against the vein wall
- It prevents air from entering the tube
Correct answer: It allows the needle to enter the vein more smoothly and reduces trauma
Bevel-up positioning allows the sharp cutting edge to penetrate the vein wall at the optimal angle with least tissue damage.
CMA Clinical Procedures and Specimen Handling 3
A hemolyzed blood specimen is most likely caused by: