BSA Stands for Body Surface Area
BSA is the abbreviation for Body Surface Area, which represents the total external surface area of the human body measured in square meters (m²). 1
Clinical Definition and Measurement
Body Surface Area (BSA) is a calculated metric derived from body weight and height that quantifies the total external surface of the body 1
BSA is typically expressed in square meters (m²) and serves as a normalization parameter for various physiological and pharmacological calculations 1
The standard reference value used for indexing cardiac measurements is 1.73 m², which represents the average adult BSA 1
Common Calculation Methods
Several validated formulas exist for calculating BSA 1:
Du Bois and Du Bois formula: One of the most widely used historical methods for BSA estimation 2
Watson formula: Commonly employed in nephrology and dialysis adequacy calculations 1
Theoretical formula: BSA = (BM × BH/35.37)^0.5, where BM is body mass in kilograms and BH is body height in meters 3
Clinical Applications
BSA is utilized across multiple medical specialties for critical calculations 1:
Chemotherapy dosing: Many cytotoxic agents are dosed based on BSA to optimize efficacy while minimizing toxicity 1
Cardiac imaging normalization: Ventricular volumes, atrial volumes, and chamber dimensions are indexed to BSA for standardized assessment 1
Dialysis adequacy: BSA calculations are essential for determining appropriate peritoneal dialysis prescriptions 1
Nuclear medicine: Radiopharmaceutical dosing in pediatric patients uses BSA-based formulas 1
Burn assessment: The extent of burns is quantified as percentage of BSA affected using tools like the Lund and Browder chart 4, 2
Important Clinical Considerations
BSA indexing may have limitations in obese patients, as adipose tissue has lower metabolic activity and water content 1
Special corrections are required for amputees to maintain accurate BSA calculations, involving both weight and surface area adjustments 1
Measurement accuracy using modern 3D scanning technology achieves precision below 1% error 2
In burn and dermatologic emergencies like Stevens-Johnson syndrome/toxic epidermal necrolysis, percentage of BSA with epidermal detachment has critical prognostic significance, with >10% BSA detachment requiring ICU or burn center admission 4