Measurements of Water in Breath and Saliva

Rapid Measurements of Water Isotopes in Human Breath and Saliva for Doubly Labeled Water Analysis

Status

Enrolling by invitation

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT03233256

Enrollment

Registered

2017-07-28

Start date

2018-02-27

Completion date

2026-12-31

Last updated

2025-12-19

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Human Energy Expenditure

Brief summary

This study proposes to demonstrate the feasibility of measuring 2H:1H and 18O:16O in saliva and breath by comparing the natural abundances of 2H:1H and 18O:16O in saliva and urine of un-dosed humans.

Detailed description

The scientific premises for this line of research are 1) challenges related to costs, the complexity of sample collection and preparation, and the level of technical skills required for Isotope-ratio mass spectrometry (IRMS) analysis have limited the adoption of the doubly labeled water (DLW) method; and 2) the investigators preliminary data demonstrates that Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) provides a valid, more rapid, and less technically challenging approach to isotopic analysis of human samples.

Interventions

PROCEDUREFeasibility of measuring 2H:1H and 18O:16O in saliva and breath.

The investigators propose to demonstrate the feasibility of measuring 2H:1H and 18O:16O in saliva and breath. The natural abundances of 2H:1H and 18O:16O of urine, saliva, and breath samples will be determined from samples obtained simultaneously from 50 relatively healthy human subjects. We will also measure 2H:1H and 18O:16O enrichments in urine, saliva, and breath of 10 relatively healthy human subjects obtained after consuming a standard DLW dose and compare the estimates of TDEE using these different matrices.

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

DIAGNOSTIC

Masking

NONE

Intervention model description

Healthy adults (18-45 yrs.) will be recruited from the local Denver area. The investigators have elected to study a relatively homogenous sample to limit the impact of age, weight, and chronic disease on isotope fractionation in breath.

Eligibility

Sex/Gender

ALL

Age

18 Years to 45 Years

Healthy volunteers

Yes

Inclusion criteria

* Healthy adult men and women, aged 18-45 yrs

Exclusion criteria

* Obesity (body mass index (BMI) \> 30 kg/m2) * Pregnant or lactating women * Self-reported acute or chronic disease (diabetes, heart diseases, thyroid diseases)

Design outcomes

Primary

Measure	Time frame	Description
Natural abundances of 2H:1H and 18O:16O in humans	Baseline	Evaluation of the natural abundances of 2H:1H and 18O:16O in urine, saliva, and breath of humans.

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026