Which of the following is commonly diagnosed by stool antigen or urea breath test?

The diagnosis of H. pylori infection, which is associated with peptic ulcer disease and gastritis, can be effectively performed using stool antigen tests or urea breath tests. These tests detect the presence of Helicobacter pylori in the gastrointestinal tract.

The stool antigen test checks for the bacteria in stool samples, indicating active infection. The urea breath test measures the presence of urease, an enzyme produced by H. pylori, by having the patient ingest a urea solution labeled with a carbon isotope. If H. pylori is present, it breaks down the urea, allowing for the detection of labeled carbon in the breath.

Other choices—such as gastritis, eosinophilic esophagitis, and esophageal varices—are not primarily diagnosed using these specific tests. While gastritis may be related to H. pylori, it is not exclusively diagnosed through these methods. Eosinophilic esophagitis is typically identified through esophageal biopsy, and esophageal varices are diagnosed using endoscopy rather than stool or breath tests. Thus, the use of stool antigen or urea breath tests is strongly associated with confirming an H. pylori infection.