Novel Noninvasive Breath Test Method for Screening Individuals at Risk for Diabetes: Response to Dillon et al. Open Access

I wish to propose consideration of another explanation for the recent results noted with [¹³C] glucose in subjects with pre- and early-stage diabetes (1). These individuals had significantly higher fasting glucose concentrations than those in the control group, which would have led to lower specific activities of [¹³C]glucose 1–3 h into the oral glucose tolerance test. This lowered specific activity would result in decreased ¹³CO₂ excretion by the lungs. This explanation is supported by many studies from ∼15 years ago that showed that the decreased glucose uptake during clamps in subjects with diabetes and impaired glucose tolerance was secondary to decreased glucose “storage” rather than changes in glucose oxidation (2,,–5).