Bioelectrical impedance analysis for measurement of body fluid volumes: a review

The need for a portable, inexpensive, accurate and safe method for measuring body composition is well established. Bioelectrical impedance analysis (BIA) has the potential to partially meet this need by estimating the water component of body composition. There are still a number of unresolved questions and limitations to the applications of BIA, however. This paper briefly reviews the theory of BIA, its application and its limitations. Recent progress in the development and validation of swept or multiple frequency BIA used to determine both extracellular water and total body water is discussed in detail.