Preliminary evaluation of a new pediatric air displacement plethysmograph for body composition assessment in infants.

A preliminary evaluation of a new air displacement plethysmography (ADP) system for body composition assessment in infants was performed on 17 subjects on 2 consecutive days. Mean (+/-SD) percent body fat (%BF) obtained from test 1 on day 1, and tests 1 and 2 on day 2 was 23.21+/-7.63, 22.94+/-7.50, and 22.55+/-7.61, respectively. Mean differences in %BF of within- (-0.39+/-0.81) and between-day tests (-0.27+/-0.97) did not significantly differ from zero. %BF 95% limits of agreements were very close (-2.0-1.2, and -2.2-1.7 for within- and between-day tests, respectively). %BF SDs (0.52 and 0.60 %BF for within- and between-day reliability, respectively) were not a function of the subject's behavioral state, body weight, or %BF. Mean %BF obtained from the 3 tests (22.90+/-7.56) was comparable with expected %BF values calculated using data from multi-compartment studies (25.84+/-8.39 and 21.93+/-4.46).