title: Estimation of body fluids with bioimpedance spectroscopy: state of the art methods and proposal of novel methods.
abstract: Determination of body fluids is a useful common practice in determination of disease mechanisms and treatments. Bioimpedance spectroscopy (BIS) methods are non-invasive, inexpensive and rapid alternatives to reference methods such as tracer dilution. However, they are indirect and their robustness and validity are unclear. In this article, state of the art methods are reviewed, their drawbacks identified and new methods are proposed. All methods were tested on a clinical database of patients receiving growth hormone replacement therapy. Results indicated that most BIS methods are similarly accurate (e.g.  <  0.5 ±   3.0% mean percentage difference for total body water) for estimation of body fluids. A new model for calculation is proposed that performs equally well for all fluid compartments (total body water, extra- and intracellular water). It is suggested that the main source of error in extracellular water estimation is due to anisotropy, in total body water estimation to the uncertainty associated with intracellular resistivity and in determination of intracellular water a combination of both.
authors.affiliation: Department of Signals and Systems, Royal Institute of Technology (KTH), Alfred Nobels Allé 10 141 52 Huddinge, Stockholm, Sweden. Department of Signal Theory and Communications, University of Alcala, ES-28871, Madrid, Spain. Department of Signal and Systems, Chalmers University of Technology, SE-41296, Gothenburg, Sweden. School of Engineering, University of Boras, SE-501 90 Borås, Sweden.
authors.forename: R
authors.initials: R
authors.lastname: Buendia
authors.forename: F
authors.initials: F
authors.lastname: Seoane
authors.forename: K
authors.initials: K
authors.lastname: Lindecrantz
authors.forename: I
authors.initials: I
authors.lastname: Bosaeus
authors.forename: R
authors.initials: R
authors.lastname: Gil-Pita
authors.forename: G
authors.initials: G
authors.lastname: Johannsson
authors.forename: L
authors.initials: L
authors.lastname: Ellegård
authors.forename: L C
authors.initials: LC
authors.lastname: Ward
mesh_terms: D001823:Body Composition; D001826:Body Fluids / Q000737:chemistry*; D058266:Dielectric Spectroscopy / Q000379:methods*; D005110:Extracellular Space / Q000737:chemistry; D006801:Humans; D042541:Intracellular Space / Q000737:chemistry; D014867:Water / Q000032:analysis
chemical_list: D014867:Water