An evaluation of the 14C-glycocholic acid breath test in the diagnosis of bacterial colonisation of the jejunum.

In order to assess the performance of the 14C-glycocholic acid breath test as an indicator of bacterial colonisation of the jejunum, 145 combined breath tests and jejunal aspirate cultures were carried out on a total of 50 subjects who had an increased probability of being colonised. Ninety-one of the 145 cultures were positive while only 31 of the breath tests were positive. This poor performance of the breath test relative to the aspirate culture can be predicted with reasonable accuracy from known bile deconjugating capabilities of bacteria found in the small intestine.