14C-labelled glycocholate is administered orally. In the presence of bacterial overgrowth in the small bowel, extensive deconjugation of 14C-glycine occurs. The labelled glycine is rapidly absorbed and metabolised to 14C-carbon dioxide which is detected in the breath.
Deconjugation may also occur if the 14C-glycocholate reaches the colon. Bile salts are usually reabsorbed in the terminal ileum and such 'false' positive results may occur in patients with abnormal ileal function e.g. in Crohn's disease.
Last reviewed 01/2018