Table 3.

Proportion of Lactulose Breath Test Methane Producers Using Two Different Thresholds in Children with Irritable Bowel Syndrome

IBS Subtype	Methane Production (≥3 ppm threshold)	Methane Production (≥ 5 ppm threshold)
IBS-Constipation (n=45)	27 (60%)	19 (42.2%)
IBS-Unsubtyped (n=35)	23 (65.7%)	18 (51.4%)
IBS-Diarrhea (n=5)	0	0
IBS-Mixed Type (n=2)	1 (50%)	1 (50%)

Methane production was defined as an individual producing any amount of breath methane following lactulose ingestion greater than or equal to the defined threshold. There were no statistically significant differences in the proportion of methane producers between irritable bowel syndrome subtypes.