What is the estimated Body Surface Area (BSA) for a 10-year-old girl weighing 57.4 kilograms (kg)?

Body Surface Area Calculation for a 10-Year-Old Girl Weighing 57.4 kg

For a 10-year-old girl weighing 57.4 kg, the estimated Body Surface Area (BSA) is approximately 1.57-1.62 m² using validated pediatric formulas, though height measurement is essential for accurate calculation.

Critical Missing Information

• Height is required for accurate BSA calculation 1, 2, 3
• All validated BSA formulas incorporate both weight and height as essential variables 2, 3, 4
• Without height, only rough estimates can be provided based on typical growth patterns 1

Estimated BSA Range (Assuming Typical Height)

For a 10-year-old girl at 57.4 kg, assuming she falls within typical height ranges:

• If height is approximately 140 cm (50th percentile): BSA ≈ 1.57 m² 3
• If height is approximately 145 cm (75th percentile): BSA ≈ 1.62 m² 3
• If height is approximately 135 cm (25th percentile): BSA ≈ 1.52 m² 3

Important Clinical Context

This child's weight of 57.4 kg is substantially above typical ranges for age, raising concerns about obesity 5:

• The CDC recommends using CDC growth charts for children over 24 months to assess BMI percentiles 1, 5
• A 10-year-old girl with this weight likely has a BMI ≥95th percentile, meeting criteria for obesity classification 5
• The American Academy of Pediatrics recommends immediate assessment for obesity-related complications in children with BMI above the 95th percentile 5

Recommended BSA Formulas for Pediatric Use

Mosteller Formula (simplest and most practical) 4, 6:

• BSA (m²) = √[(height in cm × weight in kg) / 3600]
• Widely validated across pediatric and adult populations 4
• Excellent correlation with other established formulas (r > 0.97) 4

Haycock Formula (pediatric-specific validation) 3, 4:

• BSA (m²) = weight (kg)^0.5378 × height (cm)^0.3964 × 0.024265
• Derived from geometric measurements in children and validated from premature infants to adults 3
• Provides excellent fit for BSA values from <0.2 m² to >2.0 m² (r = 0.998) 3

Gehan-George Formula (medical standard) 6:

• ln(BSA) = -3.751 + 0.422 × ln(height in cm) + 0.515 × ln(weight in kg)
• Based on 401 surface area measurements with least squares coefficient estimation 6
• Recommended as the medical standard due to robust sample size and methodology 6

Clinical Application Considerations

For medication dosing in this patient 1:

• BSA-based dosing is critical for chemotherapeutic agents and certain cardiac medications 4
• The DuBois-DuBois formula (commonly used historically) underestimates BSA in obese patients by 3-5% 4
• Mosteller or Gehan-George formulas provide more accurate estimates in overweight/obese children 4, 6

Growth assessment priorities 5, 7:

• Plot weight and height on CDC growth charts to determine BMI percentile 1, 5
• Screen for obesity-related complications including metabolic abnormalities and cardiovascular risk factors 5
• Assess dietary patterns, physical activity levels, sleep habits, and family history 5
• Serial measurements every 2-4 months initially to track BMI trajectory 5

Practical Calculation Steps

1. Obtain accurate height measurement (standing, without shoes) 1
2. Apply Mosteller formula for quick bedside calculation: BSA = √[(height × 57.4) / 3600] 4
3. Verify with Gehan-George formula if precise dosing required 6
4. Plot on CDC growth charts to assess obesity status 5, 7

Common Pitfalls to Avoid

• Never use weight-only estimates for BSA calculation in clinical decision-making 2, 3
• Avoid DuBois-DuBois formula in obese patients due to systematic underestimation 4
• Do not assume normal growth patterns given this child's elevated weight for age 5
• Recognize that BSA formulas may overestimate when using traditional equations in obese patients compared to 3D scanning methods 4