Features of assessing water sectors and body hydration status using bioimpedance body composition analyzers

Introduction . The absolute amount of total, extracellular and intracellular water of the body directly depends on the overall dimensions and component composition of the body, therefore, to assess the hydration status of the body, relative indicators of the water sectors of the body are used (as a percentage of body weight) and coefficients of water distribution in the body are used: ECW/TBW and ECW/ICW. Purpose . Determine what the difference is in assessing water distribution and body hydration status using bioimpedance analyzers of various modifications and manufacturers. Results and discussion . When the bioimpedance analyzers using to assess hydration status and the distribution of water in the body, it should be borne in mind that they have different standard values for the ECW/TBW and ECW/ICW indices. The obtained values should be interpreted only in accordance with the standards presented in the user instructions for the analyzer on which the assessment was carried out. The main differences between assessments by different analyzers are that normal index values increase with the age of the subject when measured by the InBody and Accuniq analyzers and decrease when measured by the Medass analyzer. At the same time, in the Accuniq and Medass analyzers, the normal limits depend on gender and age and have values higher than in InBody. Conclusion . Based on the results of the analysis of literature data and user instructions for the InBody, Accuniq and Medass analyzers, it was shown that different values and multidirectional trends in changes in the ECW/TBW and ECW/ICW indices with increasing age of the examined people can be associated both with different body positions during measurement using bioimpedance analyzers from different manufacturers, and with different standards for index values developed on populations with their own characteristics of hydration status.