Detection of small intestinal bacterial overgrowth (SIBO) and H. pylori infection

LHBT was performed to assess SIBO. Subjects were asked to fast for 8–12 h and avoid fermentable foods such as complex carbohydrate 24 h prior to LHBT. Also, all subjects, if applicable, stopped antibiotics for at least 4 weeks and pro-motility drugs and laxatives at least one week prior to LHBT. After oral administration of 10 g of lactulose in 200 ml of water, breath samples were collected every 20 min for 120 min. A rise in hydrogen level of ≥ 20 ppm by 60 min was considered positive for SIBO [20].

Helicobacter pylori infection was assessed by ¹³C urea breath test. All subjects, if applicable, stopped acid suppressive medication for at least 2 weeks. After 8–12 h fasting period, breath samples were collected before and 10 min after the administration of ¹³C urea capsule with 200 ml water. H. pylori infection was considered to be negative if ¹³CO₂ value was below a 2.5‰ level in the breath sample after 10 min [21, 22].