Detection of Bacterial Overgrowth in IBS Using the Lactulose H2 Breath Test: Comparison with 14C-d-Xylose and Healthy Controls
Bibliographic record
Abstract
UNLABELLED: OBJECTIVES Recent reports suggest bacterial overgrowth is commonly associated with irritable bowel syndrome (IBS) when diagnosed using the lactulose hydrogen breath test (LHBT). We employed this test to examine whether similar findings exist in a geographically distinct population of Rome II positive IBS patients and compared it to the 14C-D-xylose breath test, a test with acknowledged greater specificity for bacterial overgrowth. METHODS: In the first series, Rome II IBS patients underwent a 10 g lactulose breath test and a standardized 1 g 14C-D-xylose breath test and answered IBS symptom questionnaires. A positive test required an elevated breath hydrogen concentration within 90 min, two distinct peaks, and an increase >20 ppm. In a second series, control patients lacking gastrointestinal symptoms underwent a lactulose breath test. A positive test required an elevation of breath hydrogen >20 ppm within 90 or 180 min. These criteria were also applied to lactulose breath tests from IBS cases in series one. RESULTS: The IBS patients were predominantly female (64%) and most reported severe symptoms (80%). The majority had diarrhea predominant symptoms (63%) and only 3% were constipation predominant. In the first series, only 10% of patients had a positive lactulose breath test and 13% had a positive 14C-D-xylose test. In the second series, the number of abnormal LHBTs was much higher but no differences were found between IBS patients and controls. CONCLUSION: The lactulose breath test did not reliably detect a common association between bacterial overgrowth and IBS in our patient population.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".