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Updated: Jun 17, 2026
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Assessment of Child Anthropometry in a Large Epidemiologic Study
Published on: February 2, 2017
Within- and between-day reliability of laboratory-based body composition assessment methods
Carina M Velasquez1, Christine M Florez1, Christian Rodriguez2
1Department of Kinesiology & Sport Management, Texas Tech Universityhttps://ror.org/0405mnx93, USA.
The British Journal of Nutrition
|June 16, 2026
Summary
This study assessed the reliability of common body composition methods. Dual-energy X-ray absorptiometry (DXA) showed the best reliability, indicating excellent consistency for tracking body fat and mass.
Area of Science:
- Exercise Physiology
- Body Composition Analysis
- Measurement Reliability
Background:
- Accurate body composition assessment is crucial for health and performance monitoring.
- Understanding the reliability of different measurement techniques is essential for interpreting changes over time.
- Laboratory-based methods are frequently used but require validation for consistency.
Purpose of the Study:
- To evaluate the within- and between-day reliability of various laboratory-based body composition assessment methods.
- To compare the technical error of measurement (TEM) and intraclass correlation coefficients (ICCs) across different devices.
- To identify the most reliable methods for tracking body composition changes in healthy adults.
Main Methods:
- Eighteen healthy adults underwent repeated assessments using dual-energy X-ray absorptiometry (DXA) scanners, air displacement plethysmography (ADP), multi-frequency bioelectrical impedance analyzers (MFBIA), single-frequency BIA (SFBIA), and bioimpedance spectroscopy.
- Within-day reliability was assessed via immediate test-retest, while between-day reliability involved repeat assessments 1-2 days later.
- TEM and ICCs were calculated for body fat percentage, fat mass (FM), and fat-free mass (FFM).
Main Results:
- All methods demonstrated excellent within- and between-day reliability under standardized conditions (ICCs generally > 0.95).
- Dual-energy X-ray absorptiometry (DXA) exhibited the highest reliability, followed by one MFBIA analyzer and ADP with predicted thoracic gas volume.
- Body fat percentage TEMs ranged from 0.03-0.70% (within-day) and 0.37-1.24% (between-day).
- Fat and fat-free mass TEMs ranged from 0.02-0.53 kg (within-day) and 0.26-0.90 kg (between-day).
Conclusions:
- Laboratory-based body composition devices offer high reliability for both short-term and longer-term assessments.
- Methodological choices can impact the precision of body composition tracking, particularly for small changes.
- DXA, certain MFBIA, and ADP are recommended for reliable body composition monitoring.
Keywords:
Air displacement plethysmographyBioimpedanceBiological errorDual-energy X-ray absorptiometryTechnical errorMore Related Videos
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