Abstract: 【Abstract】 Objective In this study we summarized the changes of bioimpedance-frequency curve before and after hemodialysis with the multifrequency bioimpedance spectroscopy, and recommended a new parameter for the evaluation of volume status in hemodialysis patients Method Twenty healthy volunteers and 20 stable maintenance hemodialysis patients were included in this study. Whole-body bioimpedance was measured by using the spectroscopy with the frequency range between 100Hz and 50k Hz. The bioimpedance-frequency curves from hemodialysis patients were compared with those from healthy volunteers. Results The significance of bioimpedance-frequency curve was in accordance with that of the ECFC model. The impedance curve was significantly different between the patients before and after hemodialysis. The curve after hemodialysis was similar to that of healthy volunteers. The peak impedance value and peak frequency value were significantly different between pre- and post-hemodialysis, and between pre-hemodialysis and control group, but were indifferent between post-hemodialysis and control group. Peak impedance value was positively correlated with age, the ratio of weight to stature, and the change of weight before and after hemodialysis (r=0.631, p<0.01). Conclusion The peak impedance value is applicable for the evaluation of dry weight in hemodialysis patients.

Key words: Dry weight, Impedance of human body, Peak value of impedance