Which of the following is a non-invasive test option for diagnosing Helicobacter pylori?

• A. Urea breath test and stool antigen test.
• B. Endoscopy with biopsy.
• C. Rapid urease test on biopsy.
• D. Histology.

Answer: (A)

Testing for Helicobacter pylori can be done without endoscopy when you’re looking for active infection. The urea breath test and the stool antigen test are the two non-invasive options.

The urea breath test works because H. pylori uses urease to break down ingested labeled urea into carbon dioxide. If the bacteria are present in the stomach, the labeled CO2 shows up in the breath after the drink, indicating an active infection. This method is accurate, simple, and comfortable for the patient, and it’s also used to confirm eradication after treatment once enough time has passed.

The stool antigen test detects bacterial antigens shed in the stool. Monoclonal antibody–based versions offer high sensitivity and specificity and are useful for initial diagnosis and for confirming that the infection has been cleared after therapy.

Both of these avoid endoscopy and tissue sampling, which is why they’re considered non-invasive. In contrast, invasive options like endoscopy with biopsy, rapid urease testing on biopsy, and histology require inserting a scope and obtaining stomach tissue.