Breath Test Identifies IBS Patients Who Benefit from Antibiotics
- Authors
- A Dahlgren, P Grybäck, H Jacobsson, P M Hellström
- Journal
- Gastroenterology Research and Practice
- Year
- 2025
- DOI
- 10.1155/grp/5597071
- Study Type
- Human
- Outcome
- Neutral
- Peer Reviewed
- Yes
- Country
- Sweden
- Health Condition
- Irritable Bowel Syndrome
- Body System
- Gastrointestinal
TL;DR
A hydrogen breath test cutoff of 20 ppm helps identify IBS patients with SIBO who are more likely to improve with antibiotics.
Key Finding
A lactulose hydrogen breath test cutoff of 20 ppm can differentiate SIBO from non-SIBO cases and divide IBS patients into two groups—those with high hydrogen levels who respond to antibiotics and those with low hydrogen levels who do not.
Summary
This study tested a breath test method (lactulose hydrogen breath test) to identify small intestinal bacterial overgrowth (SIBO)—a condition where bacteria grow excessively in the small intestine—in people with irritable bowel syndrome (IBS). Researchers measured hydrogen levels in breath samples from healthy people, SIBO patients, and IBS patients, and found that a threshold of 20 parts per million could distinguish between those with and without SIBO. Importantly, IBS patients were divided into two groups: those with high hydrogen levels (who improved with antibiotics) and those with low hydrogen levels (who did not improve with antibiotics).
Practical Takeaway
This study suggests that hydrogen breath testing may help identify which IBS patients have SIBO and could benefit from antibiotic treatment. However, this is a diagnostic study focused on test accuracy rather than hydrogen water itself, so it does not directly address whether consuming hydrogen-enriched water has health benefits. The findings are relevant mainly to people interested in understanding their IBS symptoms through breath testing.
Abstract
Background: Small intestinal bacterial overgrowth (SIBO) is suggested in irritable bowel syndrome (IBS). Our primary aim was to define a discriminating threshold for a positive lactulose hydrogen breath test (LHBT) in SIBO. As a secondary aim, IBS was subdivided into SIBO and non-SIBO groups. Methods: LHBT performed in 206 subjects, 74 healthy subjects, 39 SIBO patients with intestinal lesions, 77 IBS patients, and 16 nonhydrogen producers. Using scintigraphy and LHBT, orocecal transit time was set to 80 min. Peak hydrogen levels were compared between the groups. Values are mean and 95% confidence interval. Results: Using an 80-min orocecal cutoff time, LHBT in healthy subjects had peak values of 8 (6-9) ppm and SIBO 38 (31-45) ppm (p < 0.0001). The diagnostic cutoff 20 ppm verified a sensitivity of 77% and specificity of 88% and positive and negative predictions of 77% and 88%. With the same cutoff for IBS, the mean peak value was 21 (16-26) ppm (p < 0.0001 vs. healthy) with a sensitivity of 39% and a specificity of 78% and positive and negative predictions of 77% and 84%. Separating IBS at 20 ppm, the low-hydrogen group had a peak value of 6 (5-7) ppm (ns vs. healthy), and the high-hydrogen group had a peak of 44 (38-49) ppm (p < 0.0001 vs. healthy). After antibiotics, IBS with low hydrogen remained unchanged, whereas those with high hydrogen were reduced to control (p < 0.01). Conclusion: With cutoff at 20 ppm, LHBT differentiates SIBO in patients with early high breath hydrogen peaks, subdividing IBS into non-SIBO and SIBO groups; the latter may benefit from antibiotic treatment.