Limitations in the use of 14C-glycocholate breath and stool bile acid determinations in patients with chronic diarrhea

Analysis of a modified 14C-glycocholate breath test on 165 consecutive in-patients being investigated for chronic diarrhea showed that the measurement of 14CO2 between 3 and 6 h after oral dosing of 5 microCi of 14C-glycocholic acid was of only limited use to distinguish between patients with Crohn's disease (CD), idiopathic bile salt wastage (IBW), or ileal resection (IR) from those with the irritable bowel syndrome (IBS). Continuing 14CO2 collections for up to 24 h was of little more help in establishing the presence of bacterial overgrowth syndrome (BOS) and in distinguishing between BOS and CD. Stool bile acid measurements were of use in differentiating between IBW and IBS, but did not distinguish between CD and BOS or between CD and IR. Since the range of normal values was defined by measurements in the IBS group, a positive test was specific for an organic cause of chronic diarrhea. Even so, the sensitivity of the test was relatively low: CD, 53%; IR, 23%; IBW, 14%; and BOS, 10%. We believe that the 24-h 14C-glycocholic breath test combined with the measurement of stool bile acids represents a screening test of only limited use for the identification of organic causes of chronic diarrhea.