Clinical Laboratory Chemistry Test Bank | 250+ MLS Practice Questions & Rationales

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CLINICAL LABORATORY CHEMISTRY TEST
BANK 2026-2027 | 250+ PRACTICE QUESTIONS &
RATIONALES | MEDICAL LABORATORY
SCIENCE | MLS/MLT EXAM PREP | HIGH-YIELD



Table of Contents


1. **Basic Principles & Laboratory Mathematics** (Q1–Q20)

2. **Quality Assurance &质量控制** (Q21–Q30)

3. **Carbohydrates & Diabetes Mellitus** (Q31–Q50)
4. **Lipids & Lipoproteins** (Q51–Q65)
5. **Proteins & Amino Acids** (Q66–Q80)
6. **Enzymes & Isoenzymes** (Q81–Q95)
7. **Non-Protein Nitrogen & Renal Function** (Q96–Q110)
8. **Liver Function & Bile Metabolism** (Q111–Q125)
9. **Electrolytes & Blood Gases** (Q126–Q145)
10. **Trace Elements & Vitamins** (Q146–Q155)
11. **Endocrine Chemistry** (Q156–Q175)
12. **Therapeutic Drug Monitoring & Toxicology** (Q176–Q190)
13. **Tumor Markers** (Q191–Q200)
14. **Molecular Diagnostics & Special Chemistry** (Q201–Q210)
15. **High-Yield NGN/Scenario-Based Questions** (Q211–Q220)

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# Section 1: Basic Principles & Laboratory Mathematics (Q1–Q20)


**Q1.** A serum glucose concentration is 90 mg/dL. What is the
equivalent concentration in mmol/L? (Molecular weight of glucose =
180 g/mol)
A. 5.0 mmol/L
B. 0.5 mmol/L
C. 50 mmol/L
D. 0.05 mmol/L


**Correct Answer: A – 5.0 mmol/L**
*Rationale: mg/dL to mmol/L: mg/dL ÷ 18 = mmol/L (since 180/10 =
18). 90 ÷ 18 = 5.0 mmol/L.*


**Q2.** A solution contains 5 g of NaCl in 500 mL of water. What is the
percent concentration (% w/v)?
A. 1%
B. 5%
C. 10%
D. 0.5%

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**Correct Answer: A – 1%**
*Rationale: % w/v = (grams of solute / mL of solution) × 100 = ()
× 100 = 1%.*


**Q3.** What is the molarity of a solution containing 58.5 g of NaCl
(MW = 58.5 g/mol) in 1 liter of solution?
A. 0.5 M
B. 1.0 M
C. 1.5 M
D. 2.0 M


**Correct Answer: B – 1.0 M**
*Rationale: Molarity = moles/L = (58.5 g / 58.5 g/mol) / 1 L = 1.0 M.*


**Q4.** A patient's creatinine concentration is 1.5 mg/dL. Convert this
to μmol/L (MW creatinine = 113 g/mol).
A. 133 μmol/L
B. 13.3 μmol/L
C. 1.33 μmol/L
D. 1,330 μmol/L


**Correct Answer: A – 133 μmol/L**

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*Rationale: mg/dL to μmol/L: mg/dL × 88.4 = μmol/L (since 1 mg/dL =
88.4 μmol/L). 1.5 × 88.4 = 132.6 ≈ 133 μmol/L.*


**Q5.** A serum glucose result is 5.5 mmol/L. What is the equivalent in
mg/dL?
A. 99 mg/dL
B. 55 mg/dL
C. 110 mg/dL
D. 88 mg/dL


**Correct Answer: A – 99 mg/dL**
*Rationale: mmol/L × 18 = mg/dL. 5.5 × 18 = 99 mg/dL.*


**Q6.** A 1:10 dilution of serum is made, and the test result is 200
mg/dL. What is the original concentration?
A. 2,000 mg/dL
B. 200 mg/dL
C. 20 mg/dL
D. 2,000 mg/dL


**Correct Answer: A – 2,000 mg/dL**
*Rationale: Dilution factor = 10. Original concentration = result ×
dilution factor = 200 × 10 = 2,000 mg/dL.*