Breath Test Can Distinguish IBS, Functional Dyspepsia from Healthy Volunteers

Use of a lactulose hydrogen breath test (LHBT) resulted in different postprandial symptoms allowing for differentiation of healthy volunteers from patients with functional dyspepsia (FD) or irritable bowel syndrome (IBS), according to the results of a new study.

Patients with FD/IBS had significantly more abdominal pain, bloating, borborygmi, and nausea compared with healthy volunteers, “suggesting a practical and safe method to distinguish not only between IBS and healthy volunteers … but also between FD and healthy volunteers,” reported Valeria Schindler, of the Centre for Primary Health Care at University Basel, Switzerland, and colleagues.

Previously, the LHBT had been used to differentiate between patients with IBS versus those with IBS/FD and healthy controls. In this study, Schindler and colleagues hypothesized that the same test could also differentiate those patients with FD alone. They looked at data form 146 patients with FD, 204 patients with IBS, and 50 healthy volunteers. All participants underwent LHBT that consisted of 30-g Lactulose and 400-mL Ensure. Symptoms were compared on a patient-reported Likert scale.

Based on these scores, the researchers found a significant difference between those patients with FD and healthy volunteers for LHBT-induced

  • Abdominal pain (odds ratio [OR]=246.9; 95% CI, 26.6-2290.7)
  • Abdominal bloating (OR=384.8; 95% CI, 92.9-2135.4)
  • Borborygmi (OR=9.9; 95% CI, 2.2-46.9)
  • Nausea (OR=174.4; 95% CI, 15.5-5375.5)

In a subgroup analysis of patients with IBS only compared with healthy volunteers, there was also a significant difference in LHBT-induced symptoms:

  • Abdominal pain (OR=161.2; 95% CI, 16-9.1534.8)
  • Abdominal bloating (OR=524.1; 95% CI, 114.7-3432.3)
  • Borborygmi (OR=17.7; 95% CI, 4.7-67.4)
  • Diarrhea (OR=25.8; 95% CI, 2.0-7012.6)

However, no differences in hydrogen production were found between patients with FD/IBS and healthy volunteers.

“In contrast to other nutrient studies in FD patients, our test uses a significantly higher caloric load,” the researchers wrote. “This might explain the clear discrimination between FD, IBS, and healthy volunteers based on abdominal symptoms.”

Based on the results of their study, Schindler and colleagues “think that the LHBT as an instrument including subjective as well as objective measure represents a useful tool for diagnostic work-up and to monitor and predict the therapeutic progress in FD patients in the future.”


Schindler V, Giezendanner S, Butikofer S, et al. Differentiation of functional gastrointestinal disorders from healthy volunteers by lactulose hydrogen breath test and test meal. J Gastroenterol Hepatol. 2019;34:843-851. Doi:10.1111/jgh.14551. Epub 2018 Dec 18.