What is Body Surface Area (BSA)?

Body Surface Area (BSA) is the measured or calculated surface area of the human body. For many clinical purposes, BSA is a better indicator of metabolic mass than body weight because it is less affected by abnormal adipose mass. The average BSA for adults is generally considered to be around 1.7 m².

Clinical Importance and Uses of BSA

BSA is a critical measurement in medicine, primarily used to calculate the dosage of medications with a narrow therapeutic index, such as those used in chemotherapy. Dosing based on BSA helps normalize the effect of a drug for individuals of different sizes.

• Oncology: Calculating chemotherapy doses is the most common use of BSA.
• Nephrology: It can be used to index the Glomerular Filtration Rate (GFR).
• Critical Care: It helps in determining cardiac index and fluid requirements for burn victims.

BSA Formulas Explained

Because direct measurement is impractical, BSA is always estimated using a formula. This calculator offers several widely-used options:

• Mosteller Formula (1987): The simplest and most commonly used formula today due to its ease of calculation.
• Du Bois and Du Bois Formula (1916): A classic and extensively validated formula, though slightly more complex.
• Haycock Formula (1978): Developed specifically for use in pediatric patients but also used for adults.
• Gehan and George Formula (1970): Another empirically derived formula used in clinical settings.

While BSA accounts for height and weight, it does not directly measure body fat. In cases of obesity, the correlation between BSA and metabolic rate can be less accurate. Other metrics like the Body Mass Index (BMI) or a Body Fat calculation may provide additional context about a person's overall body composition.