Lactose Breath Test in Children: Relationship Between Symptoms During the Test and Test Results

Background:Lactose malabsorption affects 70% of the world population. The hydrogen breath test (HBT) is used clinically to test for this condition. The aim of our study was to describe the relationship between symptoms experienced before and during the HBT and test results.Methods:We included children who underwent the HBT in the pediatric gastroenterology unit at Dana-Dwek Children's Hospital during a 6-month period. Previous symptoms and those experienced before and after the HBT were assessed using a questionnaire and a validated pain scale.Results:Ninety-five children were included in the study, and 66.3% had a positive HBT. Diarrhea and flatulence during the test were significantly more frequent in the group with a positive HBT compared to those with a negative test (31.7% vs. 9.4%, P = 0.016 and 69.8% vs. 40.6%, P = 0.006, respectively). The frequency of abdominal pain and bloating was similar.Conclusions:Diarrhea and flatulence during the HBT are the most specific symptoms of lactose intolerance. Abdominal pain should not be automatically attributed to lactose intolerance even in the presence of lactose malabsorption. Coupling the HBT with a real-time questionnaire facilitates interpretation of results and subsequent recommendations.