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Figure 1 | BMC Gastroenterology

Figure 1

From: 13C-Urea breath test threshold calculation and evaluation for the detection of Helicobacter pylori infection in children

Figure 1

Distribution of Δδ values in children and adolescents 30 minutes after 75 mg 13 C urea Histograms of Δδ values at 30 minutes for samples with histological validation (panel A) and for UBT samples (panel B). The nadirs of the Δδ value distributions appear to be similarly located. In panel A, the threshold Δδ value of 5.29‰ is depicted as a vertical reference line. It was calculated by logistic regression. All calculations were bootstrapped 1000-fold. In panel B, the overlaid curves correspond to two normal distributions (dotted and broken lines) and their mixed bimodal function's sum curve (continuous line). The right and left peaks presumably encompass children with and without gastric H. pylori infection, respectively. According to the goodness-of-fit-test, the empirical distribution and the mixed bimodal function were not different. The threshold value of 5.78‰ is depicted as a vertical line. It maximizes the sensitivity and specificity in discriminating between the left and right modes.

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