Body surface area or BSA is the measure of the surface area of human body. It may also be described as the measure of the total area of skin on the human body. Body surface area is mostly calculated by the doctors to determine the dosage of medicines. This article on how to calculate BSA will help you in calculating body surface area using easy formulae.
- BSA is considered to be a better indicator of the human mass than weight of the body as it is less affected by abnormal adipose mass. Therefore doctors prefer to use BSA of a person for any clinical purposes.
- There are about five different formulae for calculating BSA. Each of these formulae uses weight and height measurements to determine BSA. So, if you want to calculate BSA you have to calculate your height and weight. It would be easier for you if you measure your weight in kilograms and height in centimeters as most of the equations are derived to use these units of calculation. The final result obtained after calculating the body mass index is in m2.
- BSA formula by Mosteller
BSA (m²) = ([Height (cm) x Weight (kg)]/ 3600)1/2
- BSA formula by Dubois
BSA (m²) = [W^ (0.425)][H^(0.725)]/139.2
- BSA formula by Gehan & George
BSA (m²) = [W^ (0.51456)][H^(0.42246)]/42.5532
- BSA formula by Hancock
BSA (m²) = [W^ (0.5378)][H^(0.3964)]/41.2116
- BSA formula by Boyd
In Boyd formulae you have to use your body weight in grams and not in kilograms. To convert, use 1000 g = 1 kg.
BSA = [W^ (P)][H^(0.3)]/3118.179, where
P = 0.7285 – 0.0188Log (W)
- You can use calculator to calculate the body surface area, as the calculations are very difficult to be done manually. You may need a scientific calculator, as it is easier to calculate the exponents using a scientific calculator. While using a calculator to calculate BSA, first insert the values for height and weight and get their exponents calculated and then perform other calculations.
- There are a number of calculators to calculate BSA online. You need to enter the height and weight values in the text box and just click on the “ calculate “ button to get your body surface area calculated.
- Body surface area or BSA has many uses. Body surface area is used in the calculation of Renal clearance to get the glomerular filtration rate, cardiac index (cardiac output divided by BSA), Quetelet index. In chemotherapy and Glucocorticoid, body surface area is used to determine the dosage of medicines
Normal BSA levels
- In case of adults normal BSA is generally considered to be 1.73 m2
- In case of newborn baby it is considered to be 0.25 m2
- In case of a child of nine years it is considered to be 1.07 m2
- In case of children between 12 to 13 years it is considered to be 1.33 m2
Related Content:
while calcualting BSA through this formula- ht x wt / 3600 in this 3600 stands for what?