Yes, you should reschedule the test.
Preparation for the lactulose breath test
(LBT) is rather extensive. You cannot take antibiotics for 2 weeks before the test. You also have to avoid any food that digests slowly (e.g. nuts, coarse bread etc.) for 1 days before the test. On the day of the test, you should avoid smoking
, eating a lot. You also cannot sleep during the last hour before the test.
Hope this helps.