The short answer
DEXA provides a detailed assessment of fat mass, lean soft tissue and bone mineral. Its value for follow-up testing depends on consistent preparation, positioning and analysis.
Accuracy is closeness to a reference. Precision is repeatability. These are different concepts. Neither the scanner model nor a single report footnote establishes one universal margin of error for every person and every result.
DEXA estimates tissue compartments from X-ray attenuation and software models. It does not count individual fat cells or directly isolate skeletal muscle. See sample results and the labels they use.
What affects your DEXA results?
No measurement is perfect. Hydration, a recent large meal, a hard workout and even clothing can shift results slightly—mostly in measured lean mass. To make your scans as comparable as possible:
- Scan at a similar time of day
- Keep meals and hydration similar
- Avoid exercise before the scan
- Wear similar, metal-free clothing
- Use the same scanner each time
Different DEXA machines and software can produce slightly different numbers, so tracking your trend on one scanner matters more than comparing results between facilities. Every Body Fat USA scan is performed on the same GE Lunar Prodigy.
Why results differ between testing methods
DEXA, bioelectrical impedance, skinfolds and other methods use different measurements, assumptions and reference models. Their results may differ in either direction. A higher DEXA body fat percentage does not mean the scanner counted extra fat cells.
Use the same method and scanner to follow trends, and compare the same report fields. Learn more about body composition methods.
Reference: ISCD adult positions on body composition, preparation and precision assessment. Updated October 26, 2026.
Related questions
Body Fat USA offers $85 DEXA body composition scans and $100 RMR metabolic tests in Denver (both for $175), with reports emailed in about 5 minutes. See all FAQs
