In vivo precision of the GE Lunar iDXA densitometer for the measurement of total body composition and fat distribution in adults

Abstract

In vivo precision for body composition measurements using dual energy X-ray absorptiometry (DXA; GE Lunar iDXA, GE Healthcare, Bucks, UK) was evaluated in 52 men and women, aged 34.8 (s.d. 8.4; range 20.1-50.5) years, body mass index (25.8 kg/m(2); range 16.7-42.7 kg/m(2)). Two consecutive total body scans (with re-positioning) were conducted. Precision was excellent for all measurements, particularly for total body bone mineral content and lean tissue mass (root mean square 0.015 and 0.244 kg; coefficients of variation (CV) 0.6 and 0.5%, respectively). Precision error was CV 0.82% for total fat mass and 0.86% for percentage fat. Precision was better for gynoid (root mean square 0.397 kg; CV 0.96%) than for android fat distribution (root mean square 0.780 kg, CV 2.32%). There was good agreement between consecutive measurements for all measurements (slope (s.e.) 0.993-1.002; all R(2) = 0.99). The Lunar iDXA provided excellent precision for total body composition measurements. Research into the effect of body size on the precision of DXA body fat distribution measurements is required.