The Multi-frequency Bioelectrical Impedance Analyser, Bodystat® QuadScan 4000 device offers a quick, easy, economical, portable and non-invasive alternative to other methods of fluid assessment and Body Composition analysis, for example, radioisotope dilution, underwater weighing.
The principle of measuring the flow of current through the body (impedance) is dependent on the frequency applied. At low frequencies, the current cannot bridge the cellular membrane and will pass predominantly through the Extracellular space.
At higher frequencies penetration of the cell membrane occurs and the current is conducted by both the Extracellular Water (ECW) and Intracellular Water (ICW).
Whole Body analysis, rather than partial body analysis of arms or legs only, is measured for greater accuracy. In addition, alternative equations provide for the proximal placement of electrodes on sternum and knee to potentially monitor more sensitively the changes in fluid levels in the trunk area. Furthermore, the strategic placement of electrodes on the chest area could provide for the monitoring of change in impedance values (hence fluid shifts) in the left and right lung individually.