In vivo measurement of human body composition by dual-energy X-ray absorptiometry (DXA)

Objective: To evaluate measurements of human body composition using dual energy X-ray absorptiometry and to assess its precision and variations within and between observers as well as the influence of food and fluid intake. Design: Experimental study. Setting: District hospital, Denmark. Subjects: 17 volunteers, 12 male and 5 female. Interventions: Repeated scans under standard conditions. Main outcome measures: Precision, variations within and between observers, and influence of the degree of hydration. Results: The repeatability coefficients and the coefficients of variation (CV) were obtained for the four body compartments: tissue mass 416 g (CV 0.2%); fat mass 1117 g (CV 2.6%); lean tissue mass 1425 g (CV 0.9%), and total bone mineral content, (BMC) 109 g (CV 1.2%). There was no significant intraobserver variation. There was little interobserver variation in assessing tissue mass and BMC, but there were significant differences when judging fat and lean tissue mass. Drinking resulted in significantly increased values for tissue and lean tissue mass, which corresponded to the intake. Conclusion: DXA is precise and reproducible with little variation within and between observers. It might be useful in clinical studies.