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Overview of bioelectrical impedance analyzers
1Electricity Division, National Institute of Standards and Technology, Gaithersburg, MD Technology Administration, US Department of Commerce 20899, USA. oldham@eeel.nist.gov
The American Journal of Clinical Nutrition
|September 1, 1996
Summary
This study evaluated commercial bioelectrical impedance analyzers, finding significant errors up to 20% due to contact impedance variations. Users can perform simple tests to identify potential inaccuracies in body composition measurements.
Area of Science:
- Biomedical Engineering
- Physiological Measurement
Background:
- Bioelectrical impedance analysis (BIA) is a common method for estimating body composition.
- Accuracy of BIA devices depends on various operating parameters and potential sources of error.
Purpose of the Study:
- To assess the accuracy and sensitivity of commercial bioelectrical impedance analyzers.
- To identify operating parameters affecting measurement reliability.
Main Methods:
- Evaluation of six commercial bioelectrical impedance analyzers.
- Testing across a range of impedances simulating human body impedance.
- Assessment of sensitivity to contact impedance variations.
Main Results:
- Analyzer errors ranged from less than 1% to nearly 20% across tested impedances.
- Increased errors were observed with contact impedance at the limits of the analyzer's operating range.
- Variations in maximum current amplitude and test waveform influenced accuracy.
Conclusions:
- Commercial bioelectrical impedance analyzers exhibit variable accuracy.
- Contact impedance is a critical factor influencing measurement error.
- Users should be aware of potential errors and utilize simple tests for validation.