Comparison of a Stool Antigen Test and Serology for the Diagnosis of Helicobacter pylori Infection in Mass Survey

Serum antibody to Helicobacter pylori is tested in mass screening for gastric cancer along with the level of serum pepsinogens (PG) I and II. Recently, stool antigen tests have been developed as a new non-invasive test. We examined H. pylori infection by both serology and stool antigen test in a mass survey and compared the results to estimate applicability of stool antigen test for mass survey. A total of 994 healthy adults who received mass survey in April 2005 were tested. There were 379 men and 615 women, and the mean age was 57.7 years old. Stool samples were used to measure a H. pylori-specific antigen by enzyme immunoassay. Serum samples were tested for the prevalence of IgG antibody to H. pylori, and the level of PGs I and II was also measured to determine the presence of atrophic gastritis. Infection of H. pylori was defined as positive 61.4% and 56.4% by serology and stool antigen test, respectively. The concordance of both tests was not affected by gender and age of the subjects but difference was seen in subjects with atrophic gastritis. In particular, positivity of stool antigen test (81.8%) was significantly lower than that of serology (88.7%, p < .05) in 303 subjects with severe atrophic gastritis. Stool antigen test, which detects present but not previous infection of H. pylori, would be applicable to diagnose H. pylori infection in mass survey. Usefulness of stool antigen tests for the screening of gastric cancer should be examined.