Fat-Free Mass Qualitative Assessment with Bioelectric Impedance Analysis (BIA)

: Body composition studies, when based on two‐compartment volumetric estimates, can hardly assess nutritional states. Phase‐sensitive impedance analysis can be used to reflect directly the proportions between intra‐ and extracellular spaces (ECM/BCM), which is one of the most sensitive indexes of malnutrition. Resistance and reactance values actually measured with BIA are referred to as the series RC model; however, due to the morphology of the FFM, which is composed of cells surrounded by interstitial fluids, in reality this should be modeled as a parallel RC circuit. A nomogram developed with series‐to‐parallel transformations of resistance and reactance measured with commercial BIA on controls and patients shows interesting gender and disease sensitivity and specificity.