Value of the 14C-D-xylose breath test in patients with intestinal bacterial overgrowth

Digestion. 1985;32(2):86-91. doi: 10.1159/000199223.


18 control subjects and 18 patients, with a variety of gastrointestinal conditions were investigated using a 10-muCi 14C-D-xylose breath test. The latter also underwent quantitative bacterial studies of fluid obtained by intestinal intubation. In 14 patients a smaller dose of 3 muCi 14C-D-xylose was compared to the standard dose and there was a good correlation between the two doses. The peak value of the 14C-D-xylose test provided the best discrimination between patients with and without bacterial overgrowth. The 14C-glycocholic acid test performed in 15 patients, although as sensitive, was less discriminating. The 14C-D-xylose breath test is reliable and more specific in confirming the diagnosis of small intestinal bacterial overgrowth without having to resort to direct bacterial studies.

MeSH terms

  • Breath Tests*
  • Carbon Dioxide / metabolism
  • Chronic Disease
  • Crohn Disease / microbiology
  • Diarrhea / microbiology
  • Glycolates
  • Humans
  • Ileal Diseases / diagnosis
  • Ileum / surgery
  • Intestine, Small / microbiology*
  • Jejunum / surgery
  • Xylose*


  • Glycolates
  • glycolic acid
  • Carbon Dioxide
  • Xylose