Laboratory Science Hematology and Blood Analysis 1 — Questions and Answers
Question 1: What is the normal reference range for red blood cell (RBC) count in adult males?
- 2.5–3.5 × 10⁶/µL
- 4.5–5.9 × 10⁶/µL (Correct answer)
- 7.0–9.0 × 10⁶/µL
- 10–12 × 10⁶/µL
Correct answer: 4.5–5.9 × 10⁶/µL
The normal RBC count for adult males is 4.5–5.9 × 10⁶/µL (or 4.5–5.9 × 10¹²/L), reflecting normal oxygen-carrying capacity.
Question 2: Which anticoagulant is used in the lavender (purple) top tube for CBC testing?
- Sodium citrate
- Heparin
- EDTA (ethylenediaminetetraacetic acid) (Correct answer)
- Sodium fluoride
Correct answer: EDTA (ethylenediaminetetraacetic acid)
EDTA chelates calcium ions, preventing coagulation without altering cell morphology, making it the anticoagulant of choice for CBC testing.
Question 3: What does MCV measure in a complete blood count?
- Mean Corpuscular Volume — average size of red blood cells (Correct answer)
- Maximum Cell Velocity — RBC flow rate
- Minimal Clotting Value — coagulation threshold
- Mean Cellular Viscosity — blood thickness
Correct answer: Mean Corpuscular Volume — average size of red blood cells
MCV (Mean Corpuscular Volume) measures the average size of red blood cells and is used to classify anemias as microcytic, normocytic, or macrocytic.
Question 4: A patient with a hemoglobin of 7.5 g/dL would be classified as having which condition?
- Polycythemia
- Anemia (Correct answer)
- Leukocytosis
- Thrombocytopenia
Correct answer: Anemia
A hemoglobin below the normal threshold (typically <12 g/dL in females, <13.5 g/dL in males) indicates anemia, a deficiency in oxygen-carrying capacity.
Question 5: Which stain is routinely used to differentiate white blood cell types on a peripheral blood smear?
- Gram stain
- Ziehl-Neelsen stain
- Wright-Giemsa stain (Correct answer)
- India ink stain
Correct answer: Wright-Giemsa stain
Wright-Giemsa stain uses both eosin (acidic) and methylene blue (basic) dyes to differentially stain WBC granules and nuclear chromatin for cell identification.
Question 6: What is the function of platelets (thrombocytes) in hemostasis?
- Carry oxygen to tissues
- Fight bacterial infections
- Form the primary platelet plug at sites of vascular injury (Correct answer)
- Produce coagulation factors
Correct answer: Form the primary platelet plug at sites of vascular injury
Platelets adhere to exposed subendothelial collagen, activate, and aggregate to form a primary plug that temporarily seals vascular injuries.
Laboratory Science Hematology and Blood Analysis 1
What is the normal reference range for red blood cell (RBC) count in adult males?