[Measurement of the orocaecal transit time after an oral lactulose load--does the fasting breath hydrogen concentration affect the feasibility of the test?].

Unlabelled: The study evaluated the influence of a fasted hydrogen breath concentration on the feasibility of an ambulatory measurement of the orocaecal transit time (OCTT).

Material And Methods: Forty-two healthy subjects (36 women, 6 men, aged 27.0 +/- 8.5 year) consecutively reporting themselves for an OCTT measurement were included. Breath hydrogen concentrations were measured in the fasted state and at 10-min intervals for maximally up to 5 h after intake of a liquid 260-kcal test meal containing 10 g lactulose.

Results: Fasting breath H2 concentrations of < or = 20 ppm or > 20 ppm were found in 30 (71.4%) and 12 (28.6%) subjects, respectively. Determination of the OCTT at all 4 cut-off thresholds (5, 10, 15 and 20 ppm) was possible in 39 (92.9%) subjects. This group comprised all the subjects exhibiting a high (> 20 ppm) breath hydrogen concentration. In one subject the OCTT was determined for either the 5 or the 10 ppm threshold, in another subject for 5 ppm only, whereas in one volunteer no increase in the breath hydrogen occurred.

Conclusion: Suggested by the literature data qualification criterion, defined as fasted breath hydrogen concentration < or = 20 ppm, does not determine the feasibility of the measurement of OCTT by means of a hydrogen breath test after an oral lactulose load.