Predictive symptoms and risk factors for HMBT-Q

Predictive symptoms and risk factors for HMBT-Q

A questionnaire to identify predictive symptoms and risk factors for hydrogen and methane breath testing outcomes (HMBT‑Q).

Study status  – Recruiting


Lactulose HMBT and Glucose HMBT are simple non-invasive tests to assess whether imbalances in gut bacteria may be contributing to troublesome tummy symptoms. These imbalances in gut bacteria include small intestinal bacterial overgrowth (SIBO) and excessive methane production.

Recently there has been a lot of work done by experts in the field, to ensure that performance and interpretation of these tests are standardised, to help improve the clinical utility of these investigations. Although there is a lot of information currently available that demonstrate the risk factors and symptoms associated with these conditions, there is a lack of data demonstrating the factors that might lead to a positive test according to these new parameters. This study aims to collect data on symptoms and medical history, in patients referred for lactulose and glucose HMBT in order further improve the effectiveness of this test in the future.

Inclusion Criteria

To participate you must meet the following criteria:

  1. Undergoing Lactulose or Glucose hydrogen and methane breath testing
  2. Not currently be part of any other study



Participant involvement

All parts of the study will be done remotely. This includes signing a digital consent form and completing the questionnaire online. The questionnaire will take approximately 10 minutes to complete.


There are no direct benefits from partaking in the study, however, information we get from this study may help us to better utilise hydrogen and methane breath testing in the future.

Contact details 

Marianne Otterstad –