Comparison of total body chlorine, potassium, and water measurements in children with cystic fibrosis

Abstract

Background: Symptoms of cystic fibrosis (CF) may limit the utility of total body chlorine (TBCl) and total body potassium (TBK) measurements for assessing body fluid compartments of children. Objective: This study assessed relations among independent measurements of TBCl. TBK, and total body water (TBW) in children with CF. Design: We compared cross-sectional measurements of TBCl by in vivo neutron activation analysis, TBK by whole-body counting of 40K. TBW by D2O dilution [TBW(D2O)], and TBW from TBCl and TBK [TBW(Cl + K)] in 19 prepubertal children (13 boys) aged 7.6-12.5 y who had mild symptoms of CF. Body-composition measurements were compared with data from previous studies of healthy c..