MLPAO Hematology and Coagulation Fundamentals 1 — Questions and Answers
Question 1: What is the normal adult reference range for hemoglobin in males?
- 100-120 g/L
- 130-170 g/L (Correct answer)
- 150-200 g/L
- 110-140 g/L
Correct answer: 130-170 g/L
The normal hemoglobin range for adult males is approximately 130-170 g/L (or 13.0-17.0 g/dL). This is higher than the female reference range (120-160 g/L) due to the stimulatory effect of testosterone on erythropoiesis and the absence of menstrual blood loss.
Question 2: Which anticoagulant is used in tubes for the complete blood count (CBC)?
- Sodium citrate
- Lithium heparin
- EDTA (ethylenediaminetetraacetic acid) (Correct answer)
- Sodium fluoride
Correct answer: EDTA (ethylenediaminetetraacetic acid)
EDTA (lavender-top tube) is the anticoagulant of choice for CBC testing because it preserves cell morphology and prevents platelet clumping. EDTA chelates calcium ions, preventing coagulation while maintaining cellular integrity for accurate automated and manual cell counting.
Question 3: What does the mean corpuscular volume (MCV) measure?
- The average hemoglobin content per red blood cell
- The average size (volume) of red blood cells (Correct answer)
- The variation in red blood cell size
- The average hemoglobin concentration within red blood cells
Correct answer: The average size (volume) of red blood cells
MCV measures the average volume of individual red blood cells in femtoliters (fL). The normal range is approximately 80-100 fL. Low MCV (microcytic) suggests iron deficiency or thalassemia, while high MCV (macrocytic) suggests vitamin B12/folate deficiency or liver disease.
Question 4: Which cell type is the precursor to platelets?
- Myeloblast
- Megakaryocyte (Correct answer)
- Reticulocyte
- Monoblast
Correct answer: Megakaryocyte
Megakaryocytes are the large bone marrow cells that produce platelets through cytoplasmic fragmentation. Each megakaryocyte can produce approximately 1,000-3,000 platelets. Thrombopoietin (TPO) is the primary growth factor regulating megakaryocyte development and platelet production.
Question 5: What is the principle of impedance-based cell counting used in hematology analyzers?
- Cells are stained and counted by optical absorption
- Cells passing through an aperture cause a change in electrical resistance proportional to their volume (Correct answer)
- Cells scatter light at different angles depending on their type
- Cells are labeled with fluorescent antibodies and counted by flow cytometry
Correct answer: Cells passing through an aperture cause a change in electrical resistance proportional to their volume
Impedance (Coulter) counting works by detecting the change in electrical resistance as individual blood cells pass through a small aperture between two electrodes. Each cell causes a pulse proportional to its volume, allowing both counting and sizing of cells.
Question 6: Which condition is characterized by the presence of target cells (codocytes) on a peripheral blood smear?
- Iron deficiency anemia only
- Thalassemia and liver disease (Correct answer)
- Megaloblastic anemia
- Immune hemolytic anemia
Correct answer: Thalassemia and liver disease
Target cells are commonly seen in thalassemia (due to excess membrane relative to hemoglobin content), liver disease (due to altered membrane lipid composition), hemoglobin C disease, and post-splenectomy states. Their bull's-eye appearance results from excess membrane folding.
MLPAO Hematology and Coagulation Fundamentals 1
What is the normal adult reference range for hemoglobin in males?