LOW-COST MEASUREMENT OF BODY-COMPOSITION WITH O-18-ENRICHED WATER

Total body water (TBW) and body composition are crucial for the estima tion of nutritional status in many clinical circumstances. While the m easurement of TBW with O-18-enriched water is technically easier than with (H2O)-H-2, the cost of 10% O-18-enriched water can be regarded as prohibitive. The aim of this study was to prove that less enriched (i .e. 2%) and cheaper (about 25 ECU per dose per subject, i.e. $30) O-18 water can he used to measure TBW. In the 41 subjects studied, isotopi c equilibrium was achieved 4 hours after the isotope was administered. Plateau enrichments in urine, saliva, and plasma samples did not diff er significantly between 5 and 8 hours after the dose. TBW measurement s in 8 of these subjects showed no significant differences, regardless of whether 2% or 10% water was used. We conclude that accurate estima tes of TBW and body composition can be obtained with low-cost, 2% O-18 -enriched water.