Question 1

Which BSA formula is most accurate?

Accepted Answer

For adult patients of average size, Mosteller, Du Bois, and Haycock typically agree within 2–3%. Mosteller is the most widely used in clinical practice because it is simpler and validates well against direct measurement. Haycock outperforms the others in pediatrics, particularly in infants under 10 kg.

Question 2

What is the Mosteller formula for BSA?

Accepted Answer

BSA (m²) = √(height in cm × weight in kg ÷ 3600). It was published in NEJM in 1987 as a simplified alternative to Du Bois that is easy to compute mentally and performs comparably in adults.

Question 3

Why does chemotherapy use BSA instead of weight?

Accepted Answer

Body surface area correlates better than weight with cardiac output, glomerular filtration, and metabolic rate — the parameters that drive clearance of many cytotoxic drugs. Per-m² dosing is the clinical convention for most chemotherapy regimens, although capped BSA or AUC-based dosing (e.g., carboplatin) is increasingly used to avoid overdosing in obesity.

Question 4

Should I cap BSA in obese patients?

Accepted Answer

For some agents — most notably carboplatin (Calvert formula) and several monoclonal antibodies — yes. Many institutional protocols cap BSA at 2.0 m² to avoid systematic overdosing in obese patients, since BSA overestimates metabolically active mass at high BMI. Always check the regimen-specific guidance.

Formula	BSA
Mosteller	1.82m²
Du Bois	1.81m²
Haycock	1.83m²
Mean	1.82m²

Body Surface Area

References

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