Accuracy of an eight-point tactile-electrode impedance method in the assessment of total body water

• Published in: European journal of clinical nutrition Vol. 56; no. 11; pp. 1143 - 1148
• Main Authors: Bedogni, G, Malavolti, M, Severi, S, Poli, M, Mussi, C, Fantuzzi, AL, Battistini, N
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 01.11.2002; Nature Publishing Group
• Subjects: Accuracy; Adult; Algorithms; Biological and medical sciences; Body Composition; Body fluids; Body Water; Clinical nutrition; Deuterium; Deuterium Oxide; Dilution; Electric Impedance; Electrodes; Female; Heavy water; Humans; Impedance; Impedance method; Investigative techniques, diagnostic techniques (general aspects); Korean Peninsula; legs; Male; Measurement; Medical sciences; men; Methods; Miscellaneous. Technology; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; prediction; Reproducibility of Results; Root-mean-square errors; Sensitivity and Specificity; Water; women; Korean Peninsula; Human; Measurement; Body fluid; Healthy subject; Tactile sensor; Electrodes; Accuracy; Cross sectional study; deuterium oxide dilution; bioelectrical impedance analysis; total body water; Measurement method; Electrical impedance
• ISSN: 0954-3007; 1476-5640
• DOI: 10.1038/sj.ejcn.1601466

To establish the accuracy of an eight-polar tactile-electrode impedance method in the assessment of total body water (TBW). Transversal study. University department. Fifty healthy subjects (25 men and 25 women) with a mean (s.d.) age of 40 (12) y. TBW measured by deuterium oxide dilution; resistance (R) of arms, trunk and legs measured at frequencies of 5, 50, 250 and 500 kHz with an eight-polar tactile-electrode impedance-meter (InBody 3.0, Biospace, Seoul, Korea). An algorithm for the prediction of TBW from the whole-body resistance index at 500 kHz (height (2)/R(500) where R is the sum of the segmental resistances of arms, trunk and legs) was developed in a randomly chosen subsample of 35 subjects. This algorithm had an adjusted coefficient of determination (r2(adj)) of 0.81 (P<0.0001) and a root mean square error (RMSE) of 3.6 l (9%). Cross-validation of the predictive algorithm in the remaining 15 subjects gave an r2(adj) of 0.87 (P<0.0001) and an RMSE of 3.0 l (8%). The precision of eight-polar BIA, determined by measuring R three times a day for five consecutive days in a fasting subject, was < or =2.8% for all segments and frequencies. Eight-polar BIA is a precise method that offers accurate estimates of TBW in healthy subjects. This promising method should undergo further studies of precision and its accuracy in assessing extracellular water and appendicular body composition should be determined. Modena and Reggio Emilia University.