Medical Laboratory Science
Examination Questions and Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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1. Which anticoagulant is most commonly used for a complete blood count
(CBC)?
A. Sodium citrate
B. Heparin
C. Sodium fluoride
D. EDTA
Correct Answer: D. EDTA
Rationale: EDTA preserves cellular morphology and prevents clotting by binding
calcium, making it the preferred anticoagulant for hematology testing.
2. Hemoglobin is primarily responsible for transporting:
A. Carbon dioxide only
B. Nitrogen
C. Glucose
D. Oxygen
Correct Answer: D. Oxygen
Rationale: Hemoglobin binds oxygen in the lungs and transports it to body tissues.
,3. Which white blood cell is the most abundant in normal peripheral blood?
A. Eosinophil
B. Basophil
C. Monocyte
D. Neutrophil
Correct Answer: D. Neutrophil
Rationale: Neutrophils are the most numerous leukocytes and are the first
responders to bacterial infection.
4. Platelets are primarily responsible for:
A. Oxygen transport
B. Antibody production
C. Hormone secretion
D. Blood clot formation
Correct Answer: D. Blood clot formation
Rationale: Platelets initiate primary hemostasis by forming a platelet plug at sites
of vascular injury.
5. The liquid portion of anticoagulated blood is called:
A. Serum
B. Buffy coat
C. Lymph
D. Plasma
Correct Answer: D. Plasma
Rationale: Plasma contains clotting factors because anticoagulation prevents clot
formation.
6. Serum differs from plasma because serum:
,A. Contains more red blood cells
B. Contains platelets
C. Contains fibrinogen
D. Lacks clotting factors such as fibrinogen
Correct Answer: D. Lacks clotting factors such as fibrinogen
Rationale: Serum is obtained after blood clots, so fibrinogen and some clotting
factors are removed.
7. The normal adult site of blood cell production is the:
A. Spleen
B. Liver
C. Thymus
D. Bone marrow
Correct Answer: D. Bone marrow
Rationale: Bone marrow is the primary site of hematopoiesis in healthy adults.
8. Which laboratory department performs bacterial culture and identification?
A. Hematology
B. Chemistry
C. Immunology
D. Microbiology
Correct Answer: D. Microbiology
Rationale: Clinical microbiology identifies bacteria, fungi, viruses, and parasites
causing infection.
9. Gram-positive bacteria retain which stain after Gram staining?
A. Safranin
B. Methylene blue
, C. Acid-fast stain
D. Crystal violet
Correct Answer: D. Crystal violet
Rationale: Gram-positive organisms retain the crystal violet-iodine complex due to
their thick peptidoglycan cell wall.
10. The instrument commonly used to measure absorbance in clinical chemistry
is a:
A. Centrifuge
B. Microscope
C. Incubator
D. Spectrophotometer
Correct Answer: D. Spectrophotometer
Rationale: Spectrophotometers measure light absorbance to determine analyte
concentrations.
11. Glucose is routinely measured in the laboratory to help diagnose:
A. Asthma
B. Anemia
C. Hepatitis
D. Diabetes mellitus
Correct Answer: D. Diabetes mellitus
Rationale: Elevated blood glucose is a key laboratory finding in diabetes mellitus.
12. The universal blood donor for red blood cells is:
A. A positive
B. B negative
Examination Questions and Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. Which anticoagulant is most commonly used for a complete blood count
(CBC)?
A. Sodium citrate
B. Heparin
C. Sodium fluoride
D. EDTA
Correct Answer: D. EDTA
Rationale: EDTA preserves cellular morphology and prevents clotting by binding
calcium, making it the preferred anticoagulant for hematology testing.
2. Hemoglobin is primarily responsible for transporting:
A. Carbon dioxide only
B. Nitrogen
C. Glucose
D. Oxygen
Correct Answer: D. Oxygen
Rationale: Hemoglobin binds oxygen in the lungs and transports it to body tissues.
,3. Which white blood cell is the most abundant in normal peripheral blood?
A. Eosinophil
B. Basophil
C. Monocyte
D. Neutrophil
Correct Answer: D. Neutrophil
Rationale: Neutrophils are the most numerous leukocytes and are the first
responders to bacterial infection.
4. Platelets are primarily responsible for:
A. Oxygen transport
B. Antibody production
C. Hormone secretion
D. Blood clot formation
Correct Answer: D. Blood clot formation
Rationale: Platelets initiate primary hemostasis by forming a platelet plug at sites
of vascular injury.
5. The liquid portion of anticoagulated blood is called:
A. Serum
B. Buffy coat
C. Lymph
D. Plasma
Correct Answer: D. Plasma
Rationale: Plasma contains clotting factors because anticoagulation prevents clot
formation.
6. Serum differs from plasma because serum:
,A. Contains more red blood cells
B. Contains platelets
C. Contains fibrinogen
D. Lacks clotting factors such as fibrinogen
Correct Answer: D. Lacks clotting factors such as fibrinogen
Rationale: Serum is obtained after blood clots, so fibrinogen and some clotting
factors are removed.
7. The normal adult site of blood cell production is the:
A. Spleen
B. Liver
C. Thymus
D. Bone marrow
Correct Answer: D. Bone marrow
Rationale: Bone marrow is the primary site of hematopoiesis in healthy adults.
8. Which laboratory department performs bacterial culture and identification?
A. Hematology
B. Chemistry
C. Immunology
D. Microbiology
Correct Answer: D. Microbiology
Rationale: Clinical microbiology identifies bacteria, fungi, viruses, and parasites
causing infection.
9. Gram-positive bacteria retain which stain after Gram staining?
A. Safranin
B. Methylene blue
, C. Acid-fast stain
D. Crystal violet
Correct Answer: D. Crystal violet
Rationale: Gram-positive organisms retain the crystal violet-iodine complex due to
their thick peptidoglycan cell wall.
10. The instrument commonly used to measure absorbance in clinical chemistry
is a:
A. Centrifuge
B. Microscope
C. Incubator
D. Spectrophotometer
Correct Answer: D. Spectrophotometer
Rationale: Spectrophotometers measure light absorbance to determine analyte
concentrations.
11. Glucose is routinely measured in the laboratory to help diagnose:
A. Asthma
B. Anemia
C. Hepatitis
D. Diabetes mellitus
Correct Answer: D. Diabetes mellitus
Rationale: Elevated blood glucose is a key laboratory finding in diabetes mellitus.
12. The universal blood donor for red blood cells is:
A. A positive
B. B negative
