Figure 2

Δδ values and associated probability of histological H. pylori detection Probability of H. pylori detection by Δδ values. The probabilities of an H. pylori infection are shown as mean logistic functions with 95% confidence intervals of Δδ values at 30 minutes. In panel A, bars at the lower and upper border correspond to histologically absent and present H. pylori, respectively. The prevalence rate of H. pylori infection was 0.53. Probability values exceeding 1–0.53 = 0.47 (horizontal line) indicate H. pylori infection. This probability line joins the logistic function at the threshold Δδ value (vertical line) of 5.29‰. The logistic function is less determined (R² = 0.85) and shows a less steep increase in the probability of H. pylori infection at 60 minutes (not shown) than at 30 minutes (R² = 0.91, panel A). In panel B, bars depict 200 Δδ values randomly generated from the two distributions of the mean binormal model obtained by analysis of 1223 UBTs at 30 minutes. Bars at the lower and upper borders presumably correspond to histologically absent and present H. pylori, respectively.