CCMA Laboratory Procedures 4 — Questions and Answers
Question 1: Which additive is found in a light blue (sodium citrate) tube and is used for coagulation studies?
- Sodium citrate (Correct answer)
- EDTA
- Lithium heparin
- Potassium oxalate
Correct answer: Sodium citrate
Light blue top tubes contain sodium citrate, which chelates calcium to prevent clotting and is the required anticoagulant for PT, PTT, and INR testing.
Question 2: A patient's urine dipstick shows a positive result for nitrites. This finding is MOST suggestive of:
- Gram-negative bacterial infection (Correct answer)
- Kidney stones
- Glucose in the urine
- Hemolysis
Correct answer: Gram-negative bacterial infection
Nitrites on a urine dipstick indicate that bacteria (typically gram-negative) have converted urinary nitrates to nitrites, suggesting a urinary tract infection.
Question 3: When performing a capillary puncture on an infant, which site is preferred?
- Heel (plantar surface) (Correct answer)
- Fingertip
- Earlobe
- Thumb
Correct answer: Heel (plantar surface)
The plantar surface of the heel is the recommended site for infant capillary blood collection to avoid injuring bones and nerves in the fingers.
Question 4: Which staining method is used to visualize the presence of acid-fast organisms such as Mycobacterium tuberculosis?
- Ziehl-Neelsen stain (Correct answer)
- Gram stain
- Wright stain
- India ink stain
Correct answer: Ziehl-Neelsen stain
The Ziehl-Neelsen (acid-fast) stain uses carbol fuchsin that binds to mycolic acid in the cell walls of acid-fast bacteria like Mycobacterium tuberculosis.
Question 5: A complete blood count (CBC) result shows an elevated WBC with a left shift. This MOST likely indicates:
- Bacterial infection with increased immature neutrophils (Correct answer)
- Viral infection with lymphocytosis
- Anemia due to iron deficiency
- Thrombocytopenia
Correct answer: Bacterial infection with increased immature neutrophils
A left shift means increased bands (immature neutrophils) are released into circulation, which is a classic response to acute bacterial infection.
Question 6: Which quality control action should be taken if a control result falls outside the established range?
- Repeat the control and if still out-of-range, do not report patient results until resolved (Correct answer)
- Report patient results immediately and document the error
- Recalibrate the instrument and release all pending patient results
- Discard the reagents without further investigation
Correct answer: Repeat the control and if still out-of-range, do not report patient results until resolved
When a QC result is out of range, the run should be repeated; if still out of range, patient results must be held and the problem investigated before reporting.
Question 7: The correct angle for inserting a needle during venipuncture is:
- 15–30 degrees (Correct answer)
- 45–60 degrees
- 5–10 degrees
- 60–90 degrees
Correct answer: 15–30 degrees
A needle angle of 15–30 degrees (bevel up) is recommended for venipuncture to allow smooth entry into the vein without going through the opposite wall.
CCMA Laboratory Procedures 4
Which additive is found in a light blue (sodium citrate) tube and is used for coagulation studies?