Diagnostic testing for Helicobacter pylori can be divided into invasive and noninvasive techniques, based upon the need for endoscopy. The techniques may be direct (culture, microscopic demonstration of the organism) or indirect (using urease or an antibody response as a marker of disease). The choice of test depends upon issues such as cost, availability, clinical situation, population prevalence of infection, pretest probability of infection, and factors such as the use of proton pump inhibitors and antibiotics that may influence certain test results.
This topic review will present the indications and appropriate means of testing for H. pylori, and will also discuss the individual tests. Treatment regimens are discussed separately. (See "Treatment regimens for Helicobacter pylori".)
WHEN TO TEST
There are a number of clinical circumstances in which testing for H. pylori is considered. Recommendations for diagnostic testing for H. pylori were first proposed by the National Institutes of Health (NIH) in 1994 . More recent guidelines were published in 2006 by the European Helicobacter Study Group (EHSG)  and in 2007 by the American College of Gastroenterology (ACG) .
ACG recommendations — The ACG guidelines include the following conclusions :
- Testing for H. pylori should be performed only if the clinician plans to offer treatment for positive results
- Testing is indicated in patients with gastric MALT lymphoma, active peptic ulcer disease, or a past history of documented peptic ulcer
- The test-and-treat strategy for H. pylori (ie, test and treat if positive) is a proven management strategy for patients with uninvestigated dyspepsia who are under the age of 55 years and have no "alarm features" (bleeding, anemia, early satiety, unexplained weight loss, progressive dysphagia, odynophagia, recurrent vomiting, family history of GI cancer, previous esophagogastric malignancy)
- Deciding which test to use in which situation relies heavily upon whether a patient requires evaluation with upper endoscopy and the strengths, weaknesses, and costs of the individual tests