The cut off point for discriminating Helicobacter pylori-negative and positive patients is determined to be Δδ -value of 4 ‰, which means that an increase of the Δδ -value by more than 4 ‰ indicates an infection In comparison to bioptic diagnostics of an infection with Helicobacter pylori, the breath test achieved in clinical trials on 457 patients, a sensitivity in the range of 96.5% to 97.9% [95 %-CI: