Determination of inflammatory bowel disease activity by breath pentane analysis

Quantitative determination of breath pentane, an alkane generated by peroxidation of cellular fatty acids, has been used as a noninvasive determinant of inflammation. Herein we report the first examination of the relationship between breath pentane and intestinal inflammation in humans.

Patients (N = 33), either with a known history of inflammatory bowel disease (IBD) with symptoms of relapse or with no known history of but having symptoms consistent with IBD, were evaluated with indium-111-labeled leukocyte imaging to assess the presence of active inflammation. At the time of the indium scan, the exhaled breath of the patients was obtained via a collecting tube. Gas chromatography was used to quantify the pentane content, and these values were compared with graded indium scans.

The range of breath pentane found in our population (36 determinations in 33 patients) was from 0 to 38.4 nmol/l of exhaled air. For patients with negative scans, the mean pentane was 2.1 nmol/l, for intermediate scans 3.1, for positive scans 4.3, and for nonintestinal nuclide imaging 5.5 [P = 0.005 by analysis of variance (ANOVA)].

We have previously demonstrated the correlation of breath pentane with gross and histologic evidence of intestinal inflammation in a rodent colitis model. This current study also demonstrates that pentane analysis can be correlated with inflammatory bowel disease activity in humans.