The concept of transfer impedance in bioimpedance measurements

Abstract

Three- and four-electrode systems are commonly used for bioimpedance measurements. However, the impedance measured with these systems is actually a transfer impedance between two sets of electrodes, and not true electrical impedance between any of the electrodes. This fact is often ignored in the literature, and the consequence is a great risk for misinterpretation of measured data. In this paper we address the question of what is actually measured with a three- or four-electrode system and we elucidate some of the possible pitfalls. © 2009 Springer Berlin Heidelberg.