Bioimpedancia

ARTICLE IN PRESS
Clinical Nutrition (2004) 23, 1226–1243

www.elsevier.com/locate/clnu

ESPEN GUIDELINES

Bioelectrical impedance analysisFpart I: review of principles and methods
Ursula G. Kylea, Ingvar Bosaeusb, Antonio D. De Lorenzoc, ! ! Paul Deurenbergd, Marinos Eliae, Jose Manuel Gomezf, g h Berit Lilienthal Heitmann , Luisa Kent-Smith , Jean-Claude Melchiori, Matthias Pirlichj,Hermann Scharfetterk, Annemie M.W.J. Scholsl, Claude Pichardm,*, Composition of the ESPEN Working Group
a

Geneva University Hospital, Geneva, Switzerland Sahlgrenska University Hospital, Gothenbury, Sweden c University Rome Tor Vergata, Rome, Italy d Nutrition Consultant, Singapore e Southampton General Hospital, Southampton, UK f Hospital Universitario de Bellvitge, Barcelona, Spain g CopenhagenUniversity Hospital, Copenhagen, Denmark h University of Porto, Porto, Portugal i ! Hospital Raymond Poincare, Garches, France j ! Universitatsklinikum Charite, Berlin, Germany k Graz University of Technology, Graz, Austria l University Hospital Maastricht, Maastricht, The Netherlands m Clinical Nutrition Unit, Geneva University Hospital, Micheli-du-Crest, 24, 1211 Geneva 14, Switzerland
bReceived 3 June 2004; accepted 4 June 2004

KEYWORDS
Bioelectrical impedance analysis; Segmental bioelectrical impedance analysis; Multi-frequency bioelectrical impedance analysis;

Summary The use of bioelectrical impedance analysis (BIA) is widespread both in healthy subjects and patients, but suffers from a lack of standardized method and quality control procedures. BIA allows thedetermination of the fat-free mass (FFM) and total body water (TBW) in subjects without significant fluid and electrolyte abnormalities, when using appropriate population, age or pathology-specific BIA equations and established procedures. Published BIA equations validated against a reference method in a sufficiently large number of subjects are presented and ranked according to the standard error of theestimate.

Abbreviations: BCM, body cell mass; BF, body fat; BIA, bioelectrical impedance analysis; BIS, bioelectrical impedance spectroscopy (BIS); BMI, body mass index; BIVA, bioelectrical impedance vector analysis; DXA, dual-energy X-ray absorptiometry; ECW, extracellular water; FFM, fat-free mass; ICW, intracellular water; MF-BIA, multi-frequency bioelectrical impedance analysis; PhA, phase angle;R, resistance; SF-BIA, single frequency bioelectrical impedance analysis; TBK, total body potassium; TBW, total body water; Xc, reactance; Z, impedance. *Corresponding author. Tel.: þ 41-22-372-93-45; fax: þ 41-22-372-93-63. E-mail address: claude.pichard@medecine.unige.ch (C. Pichard). 0261-5614/$ - see front matter & 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.clnu.2004.06.004ARTICLE IN PRESS
Bioelectrical impedance analysis 1227

Bioelectrical spectroscopy; ESPEN guidelines; Fat-free mass; Total body water; Extracellular water; Intracellular water; Body cell mass

The determination of changes in body cell mass (BCM), extra cellular (ECW) and intra cellular water (ICW) requires further research using a valid model that guarantees that ECW changes do not corrupt theICW. The use of segmental-BIA, multifrequency BIA, or bioelectrical spectroscopy in altered hydration states also requires further research. ESPEN guidelines for the clinical use of BIA measurements are described in a paper to appear soon in Clinical Nutrition. & 2004 Elsevier Ltd. All rights reserved.

Introduction
This review discusses the application of bioelectrical impedance analysis (BIA).BIA is widely used in many clinical situations. Part 1 is a review of the principles and methods of BIA, the body compartments evaluated with BIA, selection criteria, and selected BIA equations reported in the literature. Part II will provide guidelines for BIA use in clinical practice.

Principles of bioelectrical impedance
The resistance (R) of a length of homogeneous conductive material...