Table 1.
The summary of the different diagnostic criteria used in our study.
Fig 1.
Summary of the basic results in the analyzed study population.
A significant, ≥20 ppm elevation of H2 level during LBT and/or less than 1.1 mmol/l rise of blood glucose during LTT were diagnostic for lactose maldigestion. Patients with negative LBT and LTT are lactose digesters. Patients with LM who had symptoms during the test were defined as lactose intolerant. Patients with an early (≤90 min) significant (≥20 ppm) rise of H2 during LBT and/or lactulose breath test were defined to have SIBO. LBT: lactose breath test; LTT: lactose tolerance test; SIBO: small intestinal bacterial overgrowth.
Fig 2.
Summary of the results based separately on the LBT, LTT, and on the combination of them.
LBT: lactose breath test; LTT: lactose tolerance test.
Fig 3.
The frequency and distribution of different symptoms in the entire study population.
Other symptoms comprise increased bowel motility, flatulence, belching, sensation of fullness in the stomach, headache, burning sensation in the stomach, or increased sensation for defecation.
Fig 4.
The frequency and distribution of different symptoms among lactose digesters/maldigesters, and among lactose tolerant/intolerant patients.
A significant, ≥20 ppm elevation of H2 level during LBT and/or less than 1.1 mmol/l rise of blood glucose during LTT were diagnostic for lactose maldigestion. Patients with negative LBT and LTT are lactose digesters. Patients with LM who had symptoms during the test were defined as lactose intolerant. Other symptoms comprise increased bowel motility, flatulence, belching, sensation of fullness in the stomach, headache, burning sensation in the stomach, or increased sensation for defecation.
Fig 5.
The diagnostic accuracy of the LBT and LTT verified by the combined results of the tests.
LBT: lactose breath test; LTT: lactose tolerance test.