www.elsevier.com/locate/clnu ESPEN GUIDELINES Bioelectrical impedance analysisFpart I: review of principles and methods Ursula G. Kyle a , Ingvar Bosaeus b , Antonio D. De Lorenzo c , Paul Deurenberg d , Marinos Elia e , Jos ! e Manuel G ! omez f , Berit Lilienthal Heitmann g , Luisa Kent-Smith h , Jean-Claude Melchior i , Matthias Pirlich j , Hermann Scharfetter k , Annemie M.W.J. Schols l , Claude Pichard m, * , Composition of the ESPEN Working Group a Geneva University Hospital, Geneva, Switzerland b 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 Copenhagen University Hospital, Copenhagen, Denmark h University of Porto, Porto, Portugal i Hospital Raymond Poincar ! e, Garches, France j Universitatsklinikum Charit ! e, 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 Received 3 June 2004; accepted 4 June 2004 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 the determination 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 the estimate. ARTICLE IN PRESS KEYWORDS Bioelectrical impedance analysis; Segmental bioelectrical impedance analysis; Multi-frequency bioelectri- cal impedance analysis; 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 Clinical Nutrition (2004) 23, 1226–1243