BSA — Du Bois Formula
Body Surface Area estimation for drug dosing
Calculator
Why use it
BSA-based dosing is standard for most chemotherapy regimens and is used in cardiac output indexing, GFR normalization, and burn area estimation.
About
The Du Bois formula is one of the oldest and most widely used methods for estimating body surface area. BSA is a critical parameter in oncology for chemotherapy dosing, in nephrology for GFR indexing, and in critical care for hemodynamic calculations. The Mosteller formula is also commonly used as a simpler alternative.
When to use
- Chemotherapy dose calculation (mg/m²)
- Cardiac index calculation (CI = CO / BSA)
- GFR normalization to 1.73 m²
- Burn percentage estimation reference
Formula
Pearls & pitfalls
- Du Bois formula was derived from only 9 subjects — yet remains widely used.
- Mosteller formula (√[height × weight / 3600]) is simpler and equally accurate for most purposes.
- Obese patients may need dose adjustments; some protocols use ideal or adjusted body weight.
- Average adult BSA is approximately 1.7 m² (range 1.5–2.2 m²).
Next steps
Apply BSA to the relevant dosing protocol. For chemotherapy, verify with institutional dose capping policies (many cap at BSA = 2.0 m²).
Evidence
Multiple validation studies confirm Du Bois and Mosteller formulas agree within 2-3% for most adult patients. Original study published in Archives of Internal Medicine, 1916.
References
- Du Bois D, Du Bois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med. 1916;17:863-871. — link