Total body water measurement in humans with 18O and 2H labeled water

Abstract

Deuterium or tritium labeled water traditionally has been used for the measurement of total body water by application of the dilution principle. However, these methods have not enjoyed wide clinical use. The use of deuterium is hampered by the tedious and time consuming nature of the analysis while the use of tritium involves a radiation hazard. In addition, exchange of the label with nonaqueous hydrogen in the body raises questions about the accuracy of total body water values. To determine if water labeled with the stable isotope 18O can yield faster and more accurate results, total body water was measured simultaneously using water labeled with both 18O and 2H. The 18O and 3H dilutions were measured by mass spectrometry. The relative precision of the body water value using the 18O method was 2% for both serum and breath analysis. The 18O was fully equilibrated within 2 to 3 hr after administration, and results from the analysis of breath CO2 could be readily obtained within 1 hr after sampling. The H2(18)O dilution space averaged 3.0% (SE = 0.4) less than the 2HHO dilution space, because the latter exchanges with nonaqueous hydrogen. For this reason, the H2(18)O dilution should be a more accurate measure of total body water than the 3HHO dilution.

Evaluation of foot-to-foot bioelectrical impedance analysis for the prediction of total body water in oncology outpatients receiving radiotherapy

“…This study therefore compared TBW predicted by foot-to-foot BIA with those measured using a deuterium oxide dilution technique. Deuterium oxide dilution is accepted as one of the 'gold standard' techniques for measuring TBW (Sheng & Huggins, 1979), although the measured dilution space needs to be corrected for overestimation of TBW because of the exchange of isotope with nonaqueous hydrogen (Schoeller et al, 1980). In our laboratory, in vitro tests have shown that the accuracy of deuterium dilution for measuring a water volume is approximately 1%.…”

Assessment of foot-to-foot bioelectrical impedance analysis for the prediction of total body water

“…We have compared the predicted total body water from a new foot-to-foot impedance machine to that measured via a deuterium oxide dilution technique. The latter technique is accepted as one of thè gold standard' methods for measuring total body water (Sheng & Huggins, 1979), although it is important to correct the measured dilution space for the overestimation of total body water due to exchange of isotope with nonaqueous hydrogen (Schoeller et al, 1980). In our laboratory, in vitro tests have shown that the accuracy of deuterium dilution for measuring a water volume is approximately 1%.…”

Skinfold thickness measurements are better predictors of body fat percentage than body mass index in male Spanish children and adolescents

“…The gold standard for measuring body composition in a two-compartment model has been underwater weighing (UWW), which measures body density from which fat and lean mass content are estimated by assuming standard ®gures for density of these components (Siri, 1961). Other robust methods include the total-body potassium method, measuring intracellular¯uid by detecting the natural radioactive 40 K isotope (Boddy et al, 1972), and measurement of total body water by dilution of a deuterium-labeled water dose (Schoeller et al, 1980). More complicated multicompartment models of body composition that include bone mass are under development (Harsha & Bray, 1996).…”