Stool antigen tests for the management of Helicobacter pylori infection.

Stool antigen tests (SATs) are noninvasive diagnostic modules for Helicobacter pylori (H. pylori) infection. Two types of SATs exist for the diagnosis of H. pylori infection, one based on enzyme immunoassay (EIA) and another on immunochromatography (ICA). SATs do not require expensive chemical agents or specified equipment; hence, they are less expensive compared with the urea breath test. Both European and Japanese guidelines have shown that EIA-based SATs using monoclonal antibodies are useful for primary diagnosis as well as for the assessment of eradication therapy. ICA-based tests do not require particular equipment and are therefore useful in developing countries. SATs are also useful for the diagnosis of H. pylori infection in children and post gastric surgery patients. SATs performed via EIA can assess H. pylori infection in a large number of subjects, almost as well as serology. Thus, SATs would be useful or detecting current infection in such a survey to identify and eradicate H. pylori infection. The accuracy of SATs is lower when the stool samples are unformed or watery, because H. pylori-specific antigens in the stool samples are diluted. Temperature and the interval between stool sample collection and measurement also affect the results of SATs. The choice of test kit depends on the sensitivity and specificity in each region and the circumstances of each patient.