DEXA (Dual-Energy X-ray Absorptiometry)
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A low-dose X-ray scan that splits the body into fat, lean, and bone — and reports it region by region — making it a clinical/research reference standard for body composition.
Detail
DEXA (DXA) uses two low-energy X-ray beams whose differential attenuation distinguishes fat mass, lean (fat-free soft) mass, and bone mineral. A whole-body scan takes ~6–10 minutes and yields total and regional values (arms, legs, trunk, android/gynoid), plus bone-density data. It is widely treated as a reference/criterion method alongside hydrostatic weighing.
Strengths: high precision and reproducibility; regional fat/lean detail (useful for tracking limb asymmetry, visceral-fat estimates, and lean-mass changes during training); measures bone density simultaneously.
Limitations: requires a clinical scanner and trained operator; small radiation dose (very low, but a consideration in pregnancy — generally avoided); cost/access; results vary by manufacturer and software, so re-test on the same machine. Hydration and recent food/exercise have a smaller effect than on BIA but standardizing conditions still improves comparability.
Key facts
- Splits body into fat, lean soft tissue, and bone; whole-body + regional breakdown.
- Reference-grade precision; also reports bone mineral density.
- Low radiation dose (avoid in pregnancy); needs a clinical scanner and trained operator.
- Results differ by machine/software — re-test on the same device.
Connections
- hydrostatic-bodpod — the other criterion-level methods.
- skinfold-assessment / bia — field methods DEXA validates against.
- body-composition-overview — method comparison.
Educational content only — not medical advice. Always consult a qualified professional for individualized guidance, especially around injury, pregnancy, or medical conditions.