I often see patients with a positive stool test for H. pylori DNA—and that doesn’t always mean an infection. The key detail: DNA in the stool = bacteria may have just passed through. Antigen in the stool = evidence of active infection. We test for H. pylori when the right symptoms are present: indigestion (dyspepsia), iron deficiency, or peptic ulcers. Not for every GI symptom such as bloating. Who’s most at risk? People from regions with high prevalence (parts of Asia, Africa, Latin America, Ea