**Part 1**

**Basics of Nephrology** 

**1** 

*Belgium* 

**Is Body Surface Area the Appropriate** 

**Index for Glomerular Filtration Rate?** 

Indexing glomerular filtration rate (GFR) for body surface area (BSA) is routine practice, but criticism has been raised on indexing GFR for BSA in children, obese and anorectic patients. Over the years other ways of indexing GFR have been proposed, including height, lean body mass, body weight, ideal weight, plasma volume, total body water and especially extracellular volume (ECV). Based on a literature review and on statistical analyses of GFR data of children, we consider the following main questions: Why do we normalize GFR for BSA? Is it really

In the late 19th century, Max Rubner introduced the 'surface' hypothesis that the metabolic rate of any animal is closely related to BSA. (Rubner, 1883) Although we know today that this assertion is not correct, the surface hypothesis was well embraced at that time and considered as a law. Since measuring heat production with direct calorimety is rather complex, BSA was seen as an alternative for reflecting the metabolic rate. The question then

In 1879, Meeh published a formula to estimate BSA from body weight. (Meeh, 1879) Meeh derived his formula in 6 adults and 10 children, using a variety of methods. Some parts of the body were marked out in geometrical patterns, which were then traced on transparent paper. Next, the surface of these areas was determined by geometry, or if the pieces of paper were very irregular, by weighing. Some of the cylindrical parts of the body were wound with strips of millimeter paper like a bandage. The widely used formula proposed by Meeh was based on the fundamental mathematical law which states that similar solids have a surface area proportional to the 2/3 power of their volumes. He used body weight to represent volume, and derived the following equation, based on dimensional analysis:

Meeh's formula remained standard until 1916 when the DuBois brothers published several manuscripts exploring different formulas to measure the BSA. To determine the surface area

necessary to index GFR? And if so, are there other or better ways to normalize GFR?

**1. Introduction** 

**2. History of BSA formulas** 

became how to measure BSA?

BSA = 0.1053 weight 2/3.

**2.2 The formula of DuBois & DuBois (1916)** 

**2.1 The formula of Meeh (1879)** 

Liesbeth Hoste and Hans Pottel

*Katholieke Universiteit Leuven Campus Kortrijk* 
