The H. pylori Stool Antigen Test is an in vitro qualitative immunochromatographic assay for the rapid detection of Helicobacter pylori antigens in human stool specimen. The test results are intended to aid in the diagnosis of H. pylori infection, to monitor the effectiveness of therapeutic treatment and to confirm the eradication of H. pylori in peptic ulcer patients.
 
Helicobacter pylori is a corkscrew-shaped, gram-negative rod that lives in the mucous layer of the stomach. H. pylori infection is now accepted as the most common cause of gastritis, and is etiologically involved in gastric ulcer, duodenal ulcer, gastric adenocarcinoma and primary gastric B-cell lymphoma.1,2 The organism is very common, infected at least half of the world's population. H. pylori infection is typically acquired in childhood. Once acquired, infection persists chronically, probably continuing in the. stomach throughout life. The damage to gastric structure and function of stomach is constant and direct. Approximately one in six of H. pylori infection develops peptic ulcer disease and a small portion of H. pylori infection leads to gastric cancer.3 The diagnostic tests for H. pylori can be classified into two categories: Invasive and Noninvasive tests. Direct detection by invasive test procedures requires an endoscopy and biopsy specimens from antrum and stomach body.4 The presence of H. pylori is then confirmed by direct culture, histological examination or rapid urease test. The endoscopy and biopsy specimens offer direct detection of active H. pylori infections. Although the procedure is highly specific and high positive predictive value, the cost and discomfort to the patients are very high. The most widely available noninvasive test is probably the serological based test. The serology test detects H. pylori specific IgG antibody in patient serum with current or prior infection.5,6 Serology test is a simple, convenient test with relative high sensitivity. The main limitation of serology test is the inability to distinguish current and past infections. Antibody may be present in the patient's serum long after eradication of the organism.6 The urease breath test (UBT) with 14C or 13C labeled urea, is a noninvasive test based on the urease activity of the organism. UBT detects active H. pylori infection and is highly sensitive and specific. The UBT requires a high density and active bacteria and should not be performed until 4 weeks after therapy to allow residual bacterial to increase to a sufficient number for detection.7
H. pylori Antigen Test is an mmunochromatographic assay that uses antibody- coated colloidal gold to detect the presence of H. pylori antigens in stool specimens. The test detects directly antigens in specimens for an active infection. The test is simple and easy to perform and the test results can be visually interpreted within 15 minutes
 
H. pylori Stool Antigen Test is a sandwich solid phase immunochromatographic assay. To perform the test, an aliquot of diluted stool sample is added to the sample well of the test cassette. The sample flows through a label pad containing H. pylori antibody coupled to red-colored colloidal gold. If the sample contains H. pylori antigens, the antigen will bind to the antibody coated on the colloidal gold particles to form antigen-antibody-gold complexes. These complexes move on the nitrocellulose membrane by capillary action toward the test line region on which H. pylori specific antibodies are immobilized. As the complexes reach the test line, they will bind to the antibody on the membrane in the form of a line. A second red control line will always appear in the result window to indicate that the test has been correctly performed and the test device functions properly. If H. pylori antigen is not present or lower than the detection limit of the test, only the control line will be visible. If the control line dose not developed, the test is invalid.