What is the primary diagnostic test for Helicobacter pylori infection?

The urea breath test is considered the primary diagnostic test for Helicobacter pylori infection due to its high specificity and sensitivity in detecting the presence of the bacteria. This non-invasive test works by measuring the amount of carbon dioxide in the breath after the patient ingests a solution containing urea labeled with a specific isotope. If H. pylori is present in the stomach, it metabolizes the urea, producing carbon dioxide that can be detected in the breath.

In contrast to the urea breath test, while endoscopy allows for direct visualization and biopsy of the gastric mucosa to detect H. pylori, it is an invasive procedure and not used as a first-line screening tool. The stool antigen test is also a reliable alternative for detecting H. pylori, especially in cases of active infection, and has been commonly used, but the urea breath test remains the gold standard. The serum antibody test, which detects antibodies against H. pylori, is less favorable for diagnosing active infections as it cannot differentiate between past and current infections and may remain positive even after successful treatment.