Final answer:
Serologic testing for IgG anti-H. pylori antibody is commonly used to diagnose H. pylori infection, but it is not the gold standard. Other tests are usually needed for confirmation.
Step-by-step explanation:
Serologic testing for IgG anti-H. pylori antibody is commonly used to diagnose H. pylori infection. This test detects the presence of IgG antibodies against H. pylori in the blood, indicating a past or current infection. However, it is important to note that serologic testing alone is not sufficient for definitive diagnosis, and it is usually followed up with other tests such as breath tests, stool tests, or stomach wall biopsies to confirm the infection.