Learn → Glossary → clinical methodology
Dual-Energy X-ray Absorptiometry (DXA)
Imaging method using two X-ray energies to differentiate bone mineral, lean soft tissue, and fat mass, providing the reference clinical measurement for bone mineral density and a widely used three-compartment body composition tool.
Also: DEXA, DXA
DXA is the operational standard for osteoporosis diagnosis (T-score ≤ -2.5 at hip or spine per WHO). For body composition, total and regional fat mass, lean mass, and appendicular skeletal muscle mass index (ASMMI) are quantified. Limitations include hydration assumptions, limited bed weight (~300 lb), and scanner cross-calibration. MNHD Ch 47 positions DXA as a workhorse but contrasts it with reference four-compartment models.
How each textbook covers it
Krause and Mahan's Food and the Nutrition Care Process, 16th ed. — Chapter 5
DEXA is the clinical gold standard for diagnosing osteoporosis (T-score <= -2.5 at hip or spine) and osteopenia (T-score -1.0 to -2.5). It also segments the body into fat mass, lean soft tissue, and bone mineral content, making it useful in obesity, HIV lipodystrophy, and sarcopenia assessment.
Modern Nutrition in Health and Disease, 12th ed. — Ch 47: Body Composition
DXA is the operational standard for osteoporosis diagnosis (T-score ≤ -2.5 at hip or spine per WHO). For body composition, total and regional fat mass, lean mass, and appendicular skeletal muscle mass index (ASMMI) are quantified. Limitations include hydration assumptions, limited bed weight (~300 lb), and scanner cross-calibration. MNHD Ch 47 positions DXA as a workhorse but contrasts it with reference four-compartment models.
Related terms
BIA, Body Composition, Bone Mineral Density, Osteoporosis, Sarcopenia