Clinical factors associated with Hydrogen and Methane Breath Testing
Research type
Research Study
Full title
Clinical factors associated with Hydrogen and Methane Breath Testing for Small Intestinal Bacterial Overgrowth and Intestinal Methanogen Overgrowth.
IRAS ID
357338
Contact name
Kelly Hard
Contact email
Sponsor organisation
SWBH NHS Trust, Research and Development
Duration of Study in the UK
0 years, 4 months, 1 days
Research summary
Hydrogen and Methane breath testing (HMBT) is used to diagnose different conditions, including Small Intestinal Bacterial Overgrowth (SIBO) and Intestinal Methanogen Overgrowth (IMO). This is done by measuring the amount of hydrogen and methane gas in the breath after following pre-test preparation and fasting. For the test a sugar drink is given and then a breath sample is taken periodically, monitoring
for a significant rise in hydrogen or methane, which would indicate having SIBO. Similarly, a high amount of methane at any time during the test would suggest having IMO.
Unfortunately, symptoms for SIBO and IMO vary between people, although it has been observed that diarrhoea is related to SIBO and constipation to IMO. Patients are referred for HMBT when they suffer from a wide range of intestinal symptoms, including bloating, nausea, excessive gas, diarrhoea or constipation.
This project focuses on the relationship between specific symptoms and other existing conditions, such as irritable bowel syndrome (IBS) or previous abdominal surgeries, with the results of HMBT. Patients referred for HMBT will complete two questionnaires asking for common intestinal symptoms, pre-existing conditions and anxiety scores to see the relationship between these and the test results.
Exploring these relationships of symptoms and pre-existing conditions helps in understanding SIBO and IMO, to help the right patients being referred to appropriate investigations, so they can be treated effectively and alleviate their symptoms.
The study would help to better understand SIBO and IMO symptoms, and search for other factors that would increase the chances of having these conditions, for more effective investigations and improving referrals.REC name
East of England - Cambridge East Research Ethics Committee
REC reference
25/EE/0267
Date of REC Opinion
8 Dec 2025
REC opinion
Further Information Favourable Opinion