bodysurfacearea

Body surface area (BSA) is a measure of the total surface area of the human body, expressed in square meters. It is used in clinical medicine to standardize measurements and to adjust physiological and pharmacological parameters between individuals.

BSA is typically estimated from readily measured body dimensions rather than measured directly. Several formulas are commonly used. Mosteller’s formula is BSA (m^2) = sqrt(height(cm) × weight(kg) / 3600), or equivalently sqrt(height(cm) × weight(kg)) / 60. The Du Bois and Du Bois formula is BSA = 0.007184 × height(cm)^0.725 × weight(kg)^0.425. Haycock’s formula is BSA = 0.024265 × height(cm)^0.3964 × weight(kg)^0.5378. All formulas assume height in centimeters and weight in kilograms.

Applications of BSA include dosing of certain medications, particularly many cytotoxic chemotherapies and some anesthetic or cardiovascular drugs, where dosage is scaled to body size. BSA is also used to index other physiological measures, such as cardiac output, glomerular filtration rate, and metabolic rate, to enable comparisons across individuals of different sizes. In clinical practice, its use helps tailor treatment intensity and monitor responses, especially in pediatric patients where body size varies widely.

Limitations of BSA arise from individual variation in body composition and aging. Formulas approximate rather than measure true surface area and may be less accurate for very obese, underweight, elderly, or pregnant individuals. Different formulas can yield noticeably different results for the same person, so the choice of formula should be appropriate to the clinical context.