Take special care It is important that you tell your doctor if: • part of your stomach has been removed (partial gastrectomy) as the reliability of the test has not been proven in these patients. • you have or suspect you have a gastric infection. • you have long term stomach problems (atrophic gastritis) as the breath test may give the wrong result and other tests may be required to confirm the presence of H. pylori. • fasting (not taking food) may have medical implications for you. • you are under 18 years.