Pediatric dose calculations by body surface area MCQs With Answer

Introduction: Pediatric dose calculations by body surface area (BSA) are vital for B. Pharm students to ensure safe, effective therapy. BSA-based dosing aligns drug exposure with physiologic factors such as cardiac output, hepatic clearance, glomerular filtration, and metabolic rate. You will use the Mosteller formula [BSA = sqrt((height in cm × weight in kg)/3600)] and Du Bois equation, scale adult doses by (BSA/1.73), and compute mg/m² regimens common in oncology and other narrow therapeutic index drugs. Mastery requires precise units (cm, kg, m²), appropriate rounding, respecting adult maximum doses, and special-population considerations (neonates, obesity). These skills reduce medication errors and optimize pediatric pharmacotherapy. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Why is BSA-based dosing used in pediatrics?

• It correlates better with physiologic determinants of drug clearance than weight alone.
• It is simpler to perform than mg/kg dosing.
• It eliminates the need for clinical monitoring.
• It guarantees identical exposure across all pediatric ages.

Correct Answer: It correlates better with physiologic determinants of drug clearance than weight alone.

Q2. Which is the correct Mosteller formula for BSA?

• BSA (m²) = sqrt([height(cm) × weight(kg)]/3600)
• BSA (m²) = sqrt([height(m) × weight(kg)]/360)
• BSA (m²) = [height(cm) + weight(kg)]/3600
• BSA (m²) = 0.1 × height(m) × weight(kg)

Correct Answer: BSA (m²) = sqrt([height(cm) × weight(kg)]/3600)

Q3. What is the correct unit for body surface area?

• Square meters (m²)
• Kilograms (kg)
• Liters (L)
• Milligrams (mg)

Correct Answer: Square meters (m²)

Q4. What standard adult BSA value is commonly used for dose scaling?

• 1.73 m²
• 1.00 m²
• 2.00 m²
• 1.50 m²

Correct Answer: 1.73 m²

Q5. Which is the correct Du Bois formula?

• BSA (m²) = 0.007184 × weight(kg)^0.425 × height(cm)^0.725
• BSA (m²) = 0.007184 × weight(kg)^0.725 × height(cm)^0.425
• BSA (m²) = 0.007184 × weight(kg)¹ × height(cm)¹
• BSA (m²) = 0.017184 × weight(kg)^0.425 × height(cm)^0.725

Correct Answer: BSA (m²) = 0.007184 × weight(kg)^0.425 × height(cm)^0.725

Q6. In which scenario is BSA-based dosing most appropriate?

• For cytotoxic chemotherapy and drugs with narrow therapeutic index requiring exposure matching
• For oral rehydration salts
• For routine antibiotics in term neonates
• For single-dose vitamin D supplementation

Correct Answer: For cytotoxic chemotherapy and drugs with narrow therapeutic index requiring exposure matching

Q7. Calculate BSA by Mosteller for a child 100 cm tall and 15 kg.

• 0.65 m²
• 0.55 m²
• 0.75 m²
• 0.95 m²

Correct Answer: 0.65 m²

Q8. If adult dose = 400 mg and child’s BSA = 0.65 m², scaled pediatric dose is approximately:

• 150 mg
• 200 mg
• 250 mg
• 300 mg

Correct Answer: 150 mg

Q9. Order: 250 mg/m². Child’s BSA = 0.78 m². What is the dose?

• 195 mg
• 180 mg
• 200 mg
• 220 mg

Correct Answer: 195 mg

Q10. What happens if height in meters is mistakenly used in the Mosteller formula instead of centimeters?

• Severely underestimates BSA and dose
• Has no effect because units cancel out
• Overestimates BSA by ~100×
• Only affects patients taller than 1 m

Correct Answer: Severely underestimates BSA and dose

Q11. Which dosing basis is standard for pediatric oncology protocols?

• mg/m² based on BSA
• mg/kg based on weight alone
• Fixed adult dose scaled by age
• Dose based on body mass index (BMI)

Correct Answer: mg/m² based on BSA

Q12. For preterm neonates, which approach is generally preferred?

• mg/kg with maturation-based adjustments
• mg/m² BSA-based dosing
• Fixed fraction of adult dose
• Dose based on chronological age only

Correct Answer: mg/kg with maturation-based adjustments

Q13. How should BSA typically be reported in practice?

• Report to two decimal places (e.g., 0.78 m²)
• Report to three significant figures
• Report as an integer percentage of 1.73
• No rounding; record full calculator output

Correct Answer: Report to two decimal places (e.g., 0.78 m²)

Q14. How should obesity be handled in pediatric BSA dosing?

• Use actual weight for Mosteller, consider dose caps not exceeding adult maximums when appropriate
• Use ideal body weight for all drugs by default
• Always reduce calculated mg/m² dose by 20% in obesity
• Switch to mg/kg dosing automatically

Correct Answer: Use actual weight for Mosteller, consider dose caps not exceeding adult maximums when appropriate

Q15. Calculated dose is 205 mg; only 200 mg scored tablets are available. What is best practice?

• Dispense 200 mg (within 10% rounding), document and monitor
• Dispense 210 mg to avoid underdosing
• Split multiple tablets to make exactly 205 mg regardless of formulation stability
• Cancel the dose; BSA dosing cannot be rounded

Correct Answer: Dispense 200 mg (within 10% rounding), document and monitor

Q16. Calculate BSA for height 90 cm and weight 12 kg (Mosteller).

• 0.55 m²
• 0.45 m²
• 0.65 m²
• 0.75 m²

Correct Answer: 0.55 m²

Q17. Order: 150 mg/m². BSA = 0.55 m². Dose?

• 82.5 mg
• 75 mg
• 90 mg
• 100 mg

Correct Answer: 82.5 mg

Q18. Calculate BSA for height 130 cm and weight 30 kg (Mosteller).

• 1.04 m²
• 0.94 m²
• 1.14 m²
• 0.84 m²

Correct Answer: 1.04 m²

Q19. A drug is ordered at 50 mg/m² for a child with BSA 1.04 m². Dose?

• 52 mg
• 50 mg
• 55 mg
• 60 mg

Correct Answer: 52 mg

Q20. Adult dose is 1,000 mg. Child BSA = 1.04 m². Scaled pediatric dose is approximately:

• 600 mg
• 520 mg
• 700 mg
• 400 mg

Correct Answer: 600 mg

Q21. What is a safe verification step after calculating a BSA-based dose?

• Independently recalculate (manual or second tool), verify units, and document result
• Trust the EHR calculator without verification
• Ask the caregiver to confirm the math
• Skip verification for non-chemotherapy drugs

Correct Answer: Independently recalculate (manual or second tool), verify units, and document result

Q22. How is a BSA nomogram typically used?

• Draw a straight line connecting height and weight and read BSA at the intersection
• Connect height to age and read weight, then compute BSA
• Trace the 50th percentile growth curve to estimate BSA
• Use height only; weight is unnecessary

Correct Answer: Draw a straight line connecting height and weight and read BSA at the intersection

Q23. Which physiologic parameters support the rationale for BSA-based dosing?

• Cardiac output, glomerular filtration, and hepatic blood flow correlate with BSA
• Only body fat correlates with BSA
• BSA correlates solely with age
• BSA is unrelated to pharmacokinetics

Correct Answer: Cardiac output, glomerular filtration, and hepatic blood flow correlate with BSA

Q24. Which statement best reflects safe practice regarding adult maximum doses?

• Never exceed the recommended adult maximum dose, even if mg/m² suggests more
• Exceed adult max if BSA is ≥1.73 m²
• Average with mg/kg to justify higher doses
• Cap only chemotherapy, not other drugs

Correct Answer: Never exceed the recommended adult maximum dose, even if mg/m² suggests more

Q25. Calculate BSA for height 80 cm and weight 10 kg (Mosteller).

• 0.47 m²
• 0.40 m²
• 0.57 m²
• 0.67 m²

Correct Answer: 0.47 m²

Q26. Adult dose = 750 mg. Child BSA = 0.47 m². Scaled pediatric dose (nearest 5 mg)?

• 205 mg
• 180 mg
• 250 mg
• 300 mg

Correct Answer: 205 mg

Q27. What is “dose banding” in BSA-based dosing?

• Group doses into predefined bands by BSA to standardize and reduce compounding variability
• Always round to the nearest 50 mg regardless of drug
• Convert all mg/m² to mg/kg equivalents
• Use adult bands for all pediatric patients

Correct Answer: Group doses into predefined bands by BSA to standardize and reduce compounding variability

Q28. Which child has the larger BSA (Mosteller, approximate)?

• Child A: 110 cm, 20 kg
• Child B: 100 cm, 25 kg
• Both equal
• Cannot be compared without BMI

Correct Answer: Child B: 100 cm, 25 kg

Q29. In the Mosteller formula, what is the denominator constant?

• 3600
• 36
• 173
• 360

Correct Answer: 3600

Q30. Height 140 cm, weight 40 kg (BSA ≈ 1.25 m²). Order: 75 mg/m². Adult maximum per dose is 90 mg. Final prescribed dose?

• 90 mg
• 93.75 mg
• 100 mg
• 80 mg

Correct Answer: 90 mg

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