Inter-Instrument Comparison of Bioimpedance Spectroscopic Analysers

摘要

Three commercially available bioimpedance spectroscopy analysers were compared for technical performanceand for their design purpose of prediction of body composition. All three analysers were electronically stable, remainingin calibration over a year, and provided highly reproducible (coefficients of variation < 0.5%) and accurate (within 0.5%of component values) measurements of impedances of a test circuit. Whole body impedances in humans were highly correlatedbetween all three instruments although significant biases between instruments were observed, particularly for themeasurement of intracellular resistance. However, when the measured impedances, and using instrument-specific resistivitycoefficients, were used to predict fat-free mass of the subjects, the difference between instruments was approximately1.7 kg fat-free mass, a value comparable with that observed for the error associated with reference methods such asmulti-compartment models of body composition. It is concluded that, with appropriate regard to standardisation of measurementprotocol, all three analysers are suitable for their design purpose of estimating body composition in humans.