Medical Laboratory Science Comprehensive Review 2026–2027 | Study Guide

Medical Laboratory Science Comprehensive Review 2026–2027

Medical Laboratory Science Comprehensive Review 2026–
2027
Clinical Concepts & Practice Questions
Part 2: Practice Questions
Question 1

A smear shows hypersegmented neutrophils and macro-ovalocytes. MCV is 118 fL. Which condition is most
likely?
A. Iron deficiency anemia
B. Megaloblastic anemia
C. Anemia of chronic disease
D. Aplastic anemia
Correct Answer: B
Rationale:
Why the Other Options Are Incorrect:
A: Iron deficiency produces microcytic, hypochromic cells with pencil cells.
C: Typically normocytic or mildly microcytic with no hypersegmentation.
D: Pancytopenia with a hypocellular marrow; cells are normocytic, not macro-ovalocytic.


Question 2

Auer rods are identified in myeloblasts. Which diagnosis is supported?
A. Chronic lymphocytic leukemia
B. Acute myeloid leukemia
C. Hairy cell leukemia
D. Multiple myeloma
Correct Answer: B
Rationale:
Why the Other Options Are Incorrect:
A: CLL shows mature small lymphocytes and smudge cells.
C: Hairy cell leukemia shows cytoplasmic projections, TRAP positive.
D: Myeloma is a plasma cell neoplasm with rouleaux; no Auer rods.


Question 3

A patient has a prolonged PT, a normal aPTT, and a normal platelet count. Which is the most likely cause?
A. Hemophilia A
B. von Willebrand disease
C. Warfarin therapy
D. Unfractionated heparin therapy
Correct Answer: C

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, Medical Laboratory Science Comprehensive Review 2026–2027
Rationale:
Why the Other Options Are Incorrect:
A: Factor VIII deficiency prolongs aPTT with a normal PT.
B: vWD usually prolongs aPTT (via low factor VIII) with a normal PT and abnormal platelet function.
D: Heparin prolongs aPTT primarily.


Question 4

Which analyte is most falsely elevated by a hemolyzed serum specimen?
A. Sodium
B. Potassium
C. Chloride
D. Calcium
Correct Answer: B
Rationale:
Why the Other Options Are Incorrect:
A, C: Higher in extracellular fluid; hemolysis causes slight dilution or negligible change.
D: Minimal effect from hemolysis.


Question 5

Which marker is most specific for myocardial injury?
A. Myoglobin
B. CK-MB
C. Cardiac troponin I
D. AST
Correct Answer: C
Rationale:
Why the Other Options Are Incorrect:
A: Rises earliest but is nonspecific (skeletal muscle).
B: Less specific and returns to baseline in 48–72 hours.
D: Found in liver, muscle, and RBCs; nonspecific.


Question 6

An emergency transfusion of plasma is needed for a patient with an unknown blood type. Which plasma is most
appropriate?
A. Group O
B. Group A
C. Group B
D. Group AB
Correct Answer: D
Rationale:

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, Medical Laboratory Science Comprehensive Review 2026–2027
Why the Other Options Are Incorrect:
A: Contains anti-A and anti-B; incompatible with A, B, AB recipients.
B: Contains anti-B; incompatible with B and AB recipients.
C: Contains anti-A; incompatible with A and AB recipients.


Question 7

Gram-positive cocci in clusters are catalase positive and coagulase positive. Identify the organism.
A. *Streptococcus pyogenes*
B. *Staphylococcus epidermidis*
C. *Staphylococcus aureus*
D. *Enterococcus faecalis*
Correct Answer: C
Rationale:
Why the Other Options Are Incorrect:
A: Chains, catalase negative, beta-hemolytic.
B: Coagulase negative, novobiocin susceptible.
D: Catalase negative, grows in 6.5% NaCl and bile esculin.


Question 8

A Gram-negative rod is lactose-fermenting, indole +, MR +, VP −, citrate −. Identify it.
A. *Klebsiella pneumoniae*
B. *Enterobacter cloacae*
C. *Salmonella enterica*
D. *Escherichia coli*
Correct Answer: D
Rationale:
Why the Other Options Are Incorrect:
A, B: VP + and citrate +, indole usually negative (Klebsiella, Enterobacter).
C: Non-lactose fermenter, indole negative, citrate variable.


Question 9

Which urine sediment finding indicates glomerular bleeding or glomerulonephritis?
A. Waxy casts
B. Hyaline casts
C. RBC casts
D. Broad casts
Correct Answer: C
Rationale:
Why the Other Options Are Incorrect:
A: Advanced stasis, chronic renal failure.

Medical Laboratory Science Comprehensive Review 2026–2027 | Practice Resource • Page 3