Contribution of the gastrointestinal tract below the stomach to the 13C-urea breath test

Background. Graham et al. [Lancet, I (1987) 1174] found a late increase of C-13 enrichment in the C-13-urea breath test 120 min after administration of labeled urea to patients without Helicobacter pylori infection. This may give false positive results. Aim. We designed this study to elucidate the contribution of the gastrointestinal tract below the stomach to the C-13-urea breath test. Patients. Twenty-eight patients with dyspeptic symptoms who gave their consent were enrolled. Methods. Patients underwent the C-13-urea breath tests both via the mouth (as usual) and the duodenum (labeled urea introduced to the second portion). Breath samples were collected at baseline, 5, 15, 30, 45, 60, 90, 120, 150 and 180 min for analysis. H. pylori status was defined by the CLOtest and by histological examination. Results. There was no late increase in C-13 enrichment of C-13-urea breath test for eight H. pylori negative patients either via the mouth or the duodenum. For those H. pylori positive patients, seventeen had no late rise C-13 enrichment of the C-13-urea breath test via the duodenum and three patients had a rise after 15 min. Conclusions. No late rise in (CO2)-C-13 excretion to cause a positive C-13-urea breath test up to 180 min after the administration of labeled urea was found in the present study (C) 2003 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.