ARKANSAS CLINICAL LABORATORY
SCIENTIST EXAM QUESTIONS WITH CORRECT
ANSWERS AND RATIONALES LATEST 2026-2027
TREND| GRADE A+ GUARANTEE
Questions 1–20: Clinical Chemistry
1. A patient's serum sodium is 140 mmol/L, chloride is 104 mmol/L, and
bicarbonate is 24 mmol/L. What is the calculated anion gap?
A. 8 mmol/L
B. 12 mmol/L
C. 16 mmol/L
D. 20 mmol/L
Correct answer: B. 12 mmol/L
Rationale: The anion gap is calculated as Na − (Cl + HCO₃). Therefore,
140 − (104 + 24) = 12 mmol/L.
2. Which enzyme is most specific for hepatocellular injury?
A. Alkaline phosphatase
B. Amylase
C. ALT
D. CK-MB
Correct answer: C. ALT
Rationale: Alanine aminotransferase (ALT) is more specific for
hepatocellular injury than AST, although significant ALT elevations can
occur in other conditions.
,3. Which analyte is most commonly used to assess long-term glycemic
control?
A. Glucose
B. Fructosamine
C. Hemoglobin A1c
D. C-peptide
Correct answer: C. Hemoglobin A1c
Rationale: HbA1c reflects average blood glucose over approximately
the preceding 2–3 months, corresponding to the lifespan of circulating
erythrocytes.
4. Which specimen is generally preferred for a routine lipid profile?
A. EDTA plasma
B. Serum
C. Citrated plasma
D. Heparinized whole blood
Correct answer: B. Serum
Rationale: Serum is commonly used for lipid testing, although validated
plasma methods may also be acceptable depending on the laboratory
analyzer and methodology.
5. An increase in unconjugated bilirubin is most strongly associated
with:
A. Biliary obstruction
B. Hemolysis
, C. Cholestasis
D. Pancreatitis
Correct answer: B. Hemolysis
Rationale: Increased destruction of red blood cells produces excess
bilirubin, resulting primarily in increased unconjugated bilirubin.
6. Which cardiac biomarker is currently preferred for detecting
myocardial injury?
A. Myoglobin
B. LDH
C. Troponin
D. AST
Correct answer: C. Troponin
Rationale: Cardiac troponins, particularly high-sensitivity cardiac
troponin assays, are highly sensitive and specific markers of myocardial
injury.
7. Which electrolyte is primarily responsible for maintaining
extracellular fluid osmolality?
A. Potassium
B. Sodium
C. Magnesium
D. Phosphate
Correct answer: B. Sodium
Rationale: Sodium is the major extracellular cation and is a major
determinant of extracellular fluid osmolality.
SCIENTIST EXAM QUESTIONS WITH CORRECT
ANSWERS AND RATIONALES LATEST 2026-2027
TREND| GRADE A+ GUARANTEE
Questions 1–20: Clinical Chemistry
1. A patient's serum sodium is 140 mmol/L, chloride is 104 mmol/L, and
bicarbonate is 24 mmol/L. What is the calculated anion gap?
A. 8 mmol/L
B. 12 mmol/L
C. 16 mmol/L
D. 20 mmol/L
Correct answer: B. 12 mmol/L
Rationale: The anion gap is calculated as Na − (Cl + HCO₃). Therefore,
140 − (104 + 24) = 12 mmol/L.
2. Which enzyme is most specific for hepatocellular injury?
A. Alkaline phosphatase
B. Amylase
C. ALT
D. CK-MB
Correct answer: C. ALT
Rationale: Alanine aminotransferase (ALT) is more specific for
hepatocellular injury than AST, although significant ALT elevations can
occur in other conditions.
,3. Which analyte is most commonly used to assess long-term glycemic
control?
A. Glucose
B. Fructosamine
C. Hemoglobin A1c
D. C-peptide
Correct answer: C. Hemoglobin A1c
Rationale: HbA1c reflects average blood glucose over approximately
the preceding 2–3 months, corresponding to the lifespan of circulating
erythrocytes.
4. Which specimen is generally preferred for a routine lipid profile?
A. EDTA plasma
B. Serum
C. Citrated plasma
D. Heparinized whole blood
Correct answer: B. Serum
Rationale: Serum is commonly used for lipid testing, although validated
plasma methods may also be acceptable depending on the laboratory
analyzer and methodology.
5. An increase in unconjugated bilirubin is most strongly associated
with:
A. Biliary obstruction
B. Hemolysis
, C. Cholestasis
D. Pancreatitis
Correct answer: B. Hemolysis
Rationale: Increased destruction of red blood cells produces excess
bilirubin, resulting primarily in increased unconjugated bilirubin.
6. Which cardiac biomarker is currently preferred for detecting
myocardial injury?
A. Myoglobin
B. LDH
C. Troponin
D. AST
Correct answer: C. Troponin
Rationale: Cardiac troponins, particularly high-sensitivity cardiac
troponin assays, are highly sensitive and specific markers of myocardial
injury.
7. Which electrolyte is primarily responsible for maintaining
extracellular fluid osmolality?
A. Potassium
B. Sodium
C. Magnesium
D. Phosphate
Correct answer: B. Sodium
Rationale: Sodium is the major extracellular cation and is a major
determinant of extracellular fluid osmolality.
