DefinitionHelicobacter pylori (H. pylori) is the bacterium (germ) responsible for most ulcers and many cases of stomach inflammation (chronic gastritis).Alternative NamesPeptic ulcer disease - H. pylori; PUD - H. pyloriHow the test is performedThere are several different methods to test for H. pylori infection.Breath test (called the carbon isotope-urea breath test or UBT):Up to 2 weeks before the test, the patient must stop taking any antibiotics, bismuth-containing medications such as Pepto-Bismol, and proton pump inhibitors (PPIs).The patient swallows a special substance containing urea (a waste product the body produces as it breaks down protein) that has been made harmlessly radioactive.If H. pylori are present, the bacteria convert the urea into carbon dioxide, which is detected and recorded in the patient's exhaled breath after 10 minutes.This test can identify almost all people who have H. pylori and confirm that the H. pylori infection has been fully treated.Blood tests:Blood tests are used to measure antibodies to H. pylori, and the results are reported in minutes.This test is not quite as accurate as the other tests.These blood tests can be used to diagnose whether an H. pylori infection is present. However, the test cannot determine whether you have an infection at the time of the test or how long you have had it because the test remains positive for years even if the infection is cured. As a result, it cannot be used to see if the infection has been eradicated.Stool test:A test to detect the genetic traces of H. pylori in the feces appears to be as accurate as the breath test for initially detecting the bacteria, and for detecting recurrences after antibiotic therapy.This test can also be used to diagnose the infection and confirm that the H. pylori infection has been eradicated.Biopsy:The most accurate way to identify the presence of H. pylori is by taking a tissue biopsy from the lining of the stomach. The only way to do this is with endoscopy, which is an invasive but safe procedure.A biopsy will be done if endoscopy was needed for other reasons. This includes diagnosing the ulcer, treating any bleeding, or making sure cancer is not present. Otherwise, many patients are treated for H. pylori based on one of the three noninvasive tests listed above.Why the test is performedTesting is most often done to diagnose H. pyloriinfection:If you have a peptic ulcer currentlyIf you had a peptic ulcer in the past and were never tested for H. pyloriAfter treatment for H. pylori infection, to make sure the infection is fully treated and that the bacteria has gone awayTesting may also be done if you need to take long-term ibuprofen or other NSAIDs drugs. Ask your doctor.Testing may also be done on some people with dyspepsia.Dyspepsia, or indigestion, is a feeling of fullness or of heat, burning, or pain in the area between the navel and the lower part of the breastbone during or after eating.Testing for H. pylori is most often done only when the indigestion is new, the person is younger than 55, and no other worrisome symptoms are present.Normal ValuesNormal results mean there is no sign that you have an H. pylori infection.What abnormal results meanAbnormal results mean that there is an infection of the stomach by H. pylori.• Patients who have H. pylori and also have an ulcer are most likely to benefit from being treated.• Patients who only have indigestion, heartburn, or acid reflux and H. pylori are less likely to benefit from treatment. The treatment does not work in all patients.• Patients who are taking long-term NSAID drugs may be treated for H. pylori, in order to prevent ulcers.ReferencesMcColl KEL. Helicobacter pylori infection. NEJM. 2010;362(17):1597-1604.Spee LA. Association between Helicobacter pylori and gastrointestinal symptoms in children. Pediatrics. 2010;125(3):e651-e669.Reviewed ByReview Date: 08/29/2011George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.