Reliability of multiple frequency bioelectrical impedance analysis: An intermachine comparison
✍ Scribed by L.C. Ward; N.M. Byrne; K. Rutter; L. Hennoste; A.P. Hills; B.H. Cornish; B.J. Thomas
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 130 KB
- Volume
- 9
- Category
- Article
- ISSN
- 1042-0533
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✦ Synopsis
The technical reliability (i.e., interinstrument and interoperator reliability) of three SEAC-swept frequency bioimpedance monitors was assessed for both errors of measurement and associated analyses. In addition, intraoperator and intrainstrument variability was evaluated for repeat measures over a 4-hour period. The measured impedance values from a range of resistance-capacitance circuits were accurate to within 3% of theoretical values over a range of 50-800 ohms. Similarly, phase was measured over the range 1°-19° with a maximum deviation of 1.3° from the theoretical value. The extrapolated impedance at zero frequency was equally well determined (±3%). However, the accuracy of the extrapolated value at infinite frequency was decreased, particularly at impedances below 50 ohms (approaching the lower limit of the measurement range of the instrument). The interinstrument/operator variation for whole body measurements were recorded on human volunteers with biases of less than ±1% for measured impedance values and less than 3% for phase. The variation in the extrapolated values of impedance at zero and infinite frequencies included variations due to operator choice of the analysis parameters but was still less than ±0.5%. Am. J. Hum. Biol. 9:63-72 © 1997 Wiley-Liss, Inc.