In-vivo precision of the GE Lunar iDXA densitometer for the measurement of appendicular and trunk lean and fat mass.

Dual energy X-ray absorptiometry (DXA) is considered to be a reference standard for the assessment of body composition, and one particular advantage is its provision of regional body composition parameters. The objective of this study was to determine the in vivo precision of the Lunar iDXA for the measurement of appendicular and trunk lean and fat mass in a heterogeneous group of adults (n=39; age 33.5 (8.3) years; BMI 24.6 (5.4) kg m(-2)). Two consecutive total body scans were performed on each participant with re-positioning between scans. There was excellent agreement between consecutive scans for measurements of both fat and lean appendicular and trunk composition (R(2)=0.99). Precision for body composition at all regions was less than 2% coefficient of variation (CV). Precision for bilateral appendicular body composition was less than 4% CV for the arms and less than 2.5% CV for the legs. Our findings indicate that the iDXA is a valuable tool for repeat measurements of regional body composition in adults.