False Negative Urea Breath Tests with H₂‐Receptor Antagonists: Interactions Between Helicobacter pylori Density and pH

Abstract

H2-receptor antagonists differ from proton pump inhibitors as high intragastric pH may cause a reduction in urease activity, unrelated to a reduced bacterial load and reversed by citric acid.

Low Dose Capsule Based 13c-Urea Breath Test Compared With the Conventional 13c-Urea Breath Test and Invasive Tests

“…The comparison of capsule based breath test with the conventional test showed that citric acid used as excipient of clinical setting, as was previously demonstrated that a change in the cutoff value within 2 and 5 would have little effect on the clinical accuracy of the test, as positive and negative results tend to group outside this range (12) . In this study powdered orange juice (pH = 3.0) was taken with the capsule to increase sensitivity of the test, although citric acid as excipient of the capsule formulation may provide an acidic microenvironment.…”

“…Although the recommendation is to avoid all proton pump inhibitors and H 2 -receptor antagonists, among omeprazole, lansoprazole and pantoprazole, the latter did not interfere in the accuracy of 13 C-urea breath test. In addition, H 2 -receptor antagonists, that increase intragastric pH, have no inhibitory effect on H. pylori density, different from proton pump inhibitors that decreases the density of H. pylori on the stomach surface (12) . Thus, the false negative effect of H 2 -receptor antagonists and proton pump inhibitors on capsule 13 C-urea breath test and the real necessity of discontinuing these medications should be further evaluated.…”

“…Thus, the false negative effect of H 2 -receptor antagonists and proton pump inhibitors on capsule 13 C-urea breath test and the real necessity of discontinuing these medications should be further evaluated. Although the effects of increasing gastric pH by H 2 -receptor antagonists and sodium bicarbonate solution and of density of H. pylori were already explored during 13 C-urea breath test in solution by Graham et al (12) that concluded H 2 -receptor antagonists differ from proton pump inhibitors as high intragastric pH may cause a reduction in urease activity, unrelated to a reduced bacterial load and reversed by citric acid. When capsule based breath test was validated against a gold standard (urease and histology), the sensitivity and the specificity were high and comparable to previous reports with 13 C-urea in capsule presentation that showed sensitivity of 95%-100% and specificity of 92-100% (7,13,25,27,28) .…”

A Retrospective Analysis of Three Non-Invasive Tests for Initial Diagnosis of <i>Helicobacter pylori</i> Infection in Children

“…Moreover, we should understand the factors that can lead to a false-positive or falsenegative. Administration of antibiotics or antacid agents within 2 -4 weeks of testing may result in a false-negative in all tests except for antibody examination [9] [10] [11]. In addition, the accuracy of UBT and antibody tests may be influenced by the age of the tested child [12].…”

Effect of different organic acids (citric, malic and ascorbic) on intragastric urease activity

“…Helicobacter pylori urease activity is enhanced by conditions that acidify the stomach and reduced by manoeuvres that increase intragastric pH such as the use of antisecretory drug therapy (reviewed in Ref 11 ).…”