Bioimpedance measurements of human body composition: critical analysis and outlook

Abstract

Bioimpedance spectroscopy represents one of the largest emerging medical device technologies. The method is generally known as impedance spectroscopy and is an inexpensive, yet extremely powerful, analytical technique for studying the electrical properties of materials. Much of what we know about biological cells and tissues comes from use of this technique in vitro. Due to the high impedance of the cell membrane, current flow through the cell is frequency dependent and this allows the fluid volume inside versus outside the body’s cells to be determined. The fluid outside the cells is primarily related to fluid volume status while the intracellular fluid also relates to the body’s cellular mass. Technical advances have removed much of the method’s basic complexities. The first commercial bioimpedance spectroscopy device for in vivo human body composition studies was introduced in 1990. Major strides have been made and the method is now poised to enter mainstream clinical medicine but the field is only in its infancy. This paper attempts to fully describe the current use of impedance in the body composition field.

Keywords::

• bioelectrical impedance
• bioimpedance
• bioimpedance spectroscopy
• body cell mass
• body composition
• body fat
• body water
• extracellular water
• intracellular water
• total body water
• weight loss

Acknowledgement

The author would like to thank Dr Ken Ellis for his brief review of this paper to help identify any major or obvious scientific mistakes.

Financial & competing interests disclosure

James Matthie is the principle founder of Xitron Technologies, Inc. In 2001, Fresenius Medical Care acquired an exclusive worldwide license for Xitron’s BIS technology. Dr Matthie is no longer affiliated with Xitron, but continues to receive payments from them. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.