The Hydrogen (H2) Breath Test: Sampling Methods and the Influence of Dietary Fibre on Fasting Level

Abstract

Three end-expiratory breath hydrogen (H₂) sampling methods were compared in a patient group (n = 12) and a laboratory staff group (n = 12) on two separate occasions. H₂ samples obtained with each method showed significantly different concentrations (p < 0.001) but no significant differences in coefficient of variation when individual triplicate samples were evaluated. There was a high correlation between the breath H₂ concentrations obtained by the three methods (r = 0.93–0.96). Fasting breath H₂ values after an overnight fast and an unrestricted diet the day before the investigation were compared with values obtained after an overnight fast and a low-fibre diet the day before the test in two patient groups (n = 39 and 39) with a comparable distribution of diagnoses and in one group of healthy volunteers (n = 17). Fasting breath H₂ concentrations were significantly lower after a low-fibre diet in the patient groups (p < 0.005) and in healthy volunteers (p < 0.02). We conclude that each of the three end-expiratory sampling methods can be chosen for use in H₂ breath tests depending on suitability and convenience and that a low-fibre diet the day before the H₂ breath test lowers fasting breath H₂ concentration.