ACS Diagnostic Chemistry Examination
Questions and Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Clinical chemistry primarily analyzes:
A. Blood cell morphology
B. Tissue architecture
C. Bacterial cultures
D. Chemical constituents of body fluids
Correct Answer: D. Chemical constituents of body fluids
Rationale: Clinical chemistry measures chemical components such as glucose,
electrolytes, enzymes, and proteins in blood and other body fluids.
2. The specimen most commonly used for clinical chemistry testing is:
A. Cerebrospinal fluid
B. Saliva
C. Urine
D. Serum
Correct Answer: D. Serum
Rationale: Serum is the specimen most frequently used because it lacks clotting
factors and is suitable for many chemistry analyses.
3. Plasma differs from serum because plasma contains:
,A. Glucose
B. Electrolytes
C. Albumin
D. Fibrinogen
Correct Answer: D. Fibrinogen
Rationale: Plasma contains clotting proteins such as fibrinogen, while serum is
obtained after clot formation.
4. Which anticoagulant is commonly used for plasma chemistry testing?
A. Sodium fluoride only
B. Citrate only
C. Heparin only for hematology
D. Lithium heparin
Correct Answer: D. Lithium heparin
Rationale: Lithium heparin is widely used for plasma chemistry because it
minimally interferes with many analytes.
5. Hemolysis primarily causes falsely increased results for:
A. Sodium
B. Chloride
C. Calcium
D. Potassium
Correct Answer: D. Potassium
Rationale: Red blood cells contain high concentrations of potassium, which are
released during hemolysis.
6. Lipemic specimens appear:
,A. Clear and colorless
B. Bright red
C. Dark green
D. Milky or cloudy
Correct Answer: D. Milky or cloudy
Rationale: High lipid concentrations scatter light, producing a cloudy appearance.
7. Icteric specimens contain increased amounts of:
A. Hemoglobin
B. Glucose
C. Albumin
D. Bilirubin
Correct Answer: D. Bilirubin
Rationale: Elevated bilirubin gives serum a yellow appearance.
8. The SI unit for substance concentration is commonly:
A. g/L only
B. mg/dL only
C. IU/L only
D. mmol/L
Correct Answer: D. mmol/L
Rationale: Many chemistry analytes are reported in millimoles per liter using SI
units.
9. A solution with pH 7 is considered:
A. Strongly acidic
B. Slightly acidic
, C. Strongly basic
D. Neutral
Correct Answer: D. Neutral
Rationale: Pure water at standard conditions has a pH of 7.
10. A buffer functions to:
A. Increase acidity rapidly
B. Destroy proteins
C. Remove electrolytes
D. Resist changes in pH
Correct Answer: D. Resist changes in pH
Rationale: Buffers minimize pH changes when acids or bases are added.
11. The principal extracellular cation is:
A. Potassium
B. Magnesium
C. Calcium
D. Sodium
Correct Answer: D. Sodium
Rationale: Sodium is the major positively charged ion in extracellular fluid.
12. The principal intracellular cation is:
A. Sodium
B. Calcium
C. Chloride
D. Potassium
Correct Answer: D. Potassium
Questions and Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Clinical chemistry primarily analyzes:
A. Blood cell morphology
B. Tissue architecture
C. Bacterial cultures
D. Chemical constituents of body fluids
Correct Answer: D. Chemical constituents of body fluids
Rationale: Clinical chemistry measures chemical components such as glucose,
electrolytes, enzymes, and proteins in blood and other body fluids.
2. The specimen most commonly used for clinical chemistry testing is:
A. Cerebrospinal fluid
B. Saliva
C. Urine
D. Serum
Correct Answer: D. Serum
Rationale: Serum is the specimen most frequently used because it lacks clotting
factors and is suitable for many chemistry analyses.
3. Plasma differs from serum because plasma contains:
,A. Glucose
B. Electrolytes
C. Albumin
D. Fibrinogen
Correct Answer: D. Fibrinogen
Rationale: Plasma contains clotting proteins such as fibrinogen, while serum is
obtained after clot formation.
4. Which anticoagulant is commonly used for plasma chemistry testing?
A. Sodium fluoride only
B. Citrate only
C. Heparin only for hematology
D. Lithium heparin
Correct Answer: D. Lithium heparin
Rationale: Lithium heparin is widely used for plasma chemistry because it
minimally interferes with many analytes.
5. Hemolysis primarily causes falsely increased results for:
A. Sodium
B. Chloride
C. Calcium
D. Potassium
Correct Answer: D. Potassium
Rationale: Red blood cells contain high concentrations of potassium, which are
released during hemolysis.
6. Lipemic specimens appear:
,A. Clear and colorless
B. Bright red
C. Dark green
D. Milky or cloudy
Correct Answer: D. Milky or cloudy
Rationale: High lipid concentrations scatter light, producing a cloudy appearance.
7. Icteric specimens contain increased amounts of:
A. Hemoglobin
B. Glucose
C. Albumin
D. Bilirubin
Correct Answer: D. Bilirubin
Rationale: Elevated bilirubin gives serum a yellow appearance.
8. The SI unit for substance concentration is commonly:
A. g/L only
B. mg/dL only
C. IU/L only
D. mmol/L
Correct Answer: D. mmol/L
Rationale: Many chemistry analytes are reported in millimoles per liter using SI
units.
9. A solution with pH 7 is considered:
A. Strongly acidic
B. Slightly acidic
, C. Strongly basic
D. Neutral
Correct Answer: D. Neutral
Rationale: Pure water at standard conditions has a pH of 7.
10. A buffer functions to:
A. Increase acidity rapidly
B. Destroy proteins
C. Remove electrolytes
D. Resist changes in pH
Correct Answer: D. Resist changes in pH
Rationale: Buffers minimize pH changes when acids or bases are added.
11. The principal extracellular cation is:
A. Potassium
B. Magnesium
C. Calcium
D. Sodium
Correct Answer: D. Sodium
Rationale: Sodium is the major positively charged ion in extracellular fluid.
12. The principal intracellular cation is:
A. Sodium
B. Calcium
C. Chloride
D. Potassium
Correct Answer: D. Potassium
