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)

Non-invasive testing for Helicobacter pylori means you can diagnose without using endoscopy or taking tissue samples. The two main non-invasive options are the urea breath test and the stool antigen test. The urea breath test works because H. pylori produces urease; when you ingest urea labeled with a carbon isotope, the bacteria break it down and the labeled CO2 is detected in your breath, indicating an active infection. The stool antigen test looks for H. pylori–specific antigens shed in the stool, which also indicates active infection. These approaches are convenient for initial diagnosis and for confirming eradication after treatment, because they reflect current infection without requiring tissue. Invasive options—endoscopy with biopsy, rapid urease test on biopsy, and histology—require obtaining a tissue sample, which is why they aren’t non-invasive. So the non-invasive test option is the combination of the urea breath test and stool antigen test.