Background: The purpose of the present paper was to assess the reproducibility of the C-urea breath test (C-UBT) and its ability to reflect the level of Helicobacter pylori -associated inflammation.
Methods: Asymptomatic H. pylori -positive subjects ( n = 21) performed the C-UBT six times. The H. pylori -positive symptomatic subjects ( n = 55) performed the C-UBT and had antral biopsies taken for histopathology, culture, urease activity assay and myeloperoxidase activity assay.
Results: No significant intraindividual variation in C-UBT results were observed for the asymptomatic subjects. The C-UBT results were significantly higher in symptomatic subjects with a moderate to severe gastritis compared to a mild gastritis and to no inflammation (34.5 ± 4.4 vs 17.7 ± 2.8 vs 1.7 ± 0.1, respectively, P < 0.01). The C-UBT results significantly correlated with urease ( r = 0.55) and myeloperoxidase activity ( r = 0.82) but not with bacterial load.
Conclusion: The C-UBT is a reproducible determinant of H. pylori infection and non-invasively assesses the severity of antral inflammation.
Helicobacter pylori is the primary cause of gastritis and peptic ulcer disease and has been linked to the onset of gastric cancer in some individuals. This organism has been shown to infect more than 50% of the world's population with an incidence of up to 80% in developing countries. The need for a simple, non-invasive test for the detection of H. pylori infection was met by the development of the urea breath test, which allowed infection status to be known without the need for costly and invasive endoscopies. The urea breath tests have since been refined with the introduction of test meals to delay gastric emptying, shortened sampling periods and with the introduction of a stable isotope (C) alternative to radioactive C-urea. With a sensitivity of 98% and a specificity of 97%, the C-urea breath test (C-UBT) is rapidly becoming the test of choice in determining the efficacy of H. pylori eradication following antibiotic therapy.
At present, many strategies exist for the treatment of H. pylori infection, but increased resistance to current antibiotics is beginning to impair our ability to eradicate this organism. There is therefore a need for the introduction of novel therapies against H. pylori that are without the bacterial resistance experienced with current antibiotics. Moreover, there is a requirement for a non-invasive method of assessing the efficacy of H. pylori therapies during trials without the need for endoscopy where only the stool antigen test currently exists. Hence, the present study aims to investigate the ability of the C-UBT to assess H. pylori infection and associated disease in both asymptomatic and symptomatic individuals.
The C-UBT involves the ingestion of an isotopically labeled (C) urea tablet that is hydrolyzed to ammonia and labeled CO2 by H. pylori urease activity. Exhaled CO2 is then detected in the breath of patients by isotope ratio mass spectrometry. It has recently been proposed that the C-UBT can be used as a non-invasive tool to predict H. pylori load in vivo and the severity of H. pylori -associated gastritis. This suggests that the C-UBT has the potential to provide a non-invasive index of bacterial growth and associated disease in addition to assessing the efficacy of therapeutic modalities in infected populations.
In order to interpret the breath test results in any quantitative manner the reproducibility of the C-UBT needs to be assessed. Therefore, the primary aim of the present study was to assess the intraindividual variation of the C-UBT in a group of asymptomatic H. pylori -positive individuals. The second aim of the present study was to compare C-UBT results to H. pylori load, the severity of H. pylori -associated gastritis, H. pylori urease activity and mucosal myeloperoxidase (MPO) activity, a marker of intestinal inflammation in H. pylori -positive symptomatic patients.