Evaluation of the Helicobacter pylori stool antigen test (HpSA) for the detection of Helicobacter pylori infection and comparison with other methods

BACKGROUND/AIMS: Several invasive and non-invasive methods are available for the detection of H. pylori infection. The accuracy of anti-H. pylori antibodies in serum is low. There is a need for a quick, inexpensive and reliable non-invasive test to detect H. pylori. The aim of this study was to evaluate the enzyme immunoassay for the detection of H. pylori antigen in stool in the Turkish population and compare it to other methods. METHODOLOGY: 50 patients who were admitted to Hacettepe University Department of Internal Medicine, Division of Gastroenterology with the symptom of dyspepsia for whom the indication of upper gastrointestinal endoscopy was present were included in the study. With their permission stool samples were taken. The patients were evaluated with histology, culture, serology, rapid urease test and HpSA (Helicobacter pylori Stool Antigen test). Forty-one patients had gastritis and biopsies were taken from those. RESULTS: Excluding HpSA if three of the rest of four methods were positive, patients were accepted as H. pylori positive. Nineteen patients were positive for H. pylori, 22 were negative. HpSA was positive in 16 of 19. The sensitivity and specificity of the methods were as follows: histology 100% sensitive, and 86% specific, culture 63% and 100%, HpIgG 58% and 73%, rapid urease test 89% and 82%, respectively. The results were as 84% and 82% for HpSA. Comparing with the 'Gold Standard' histology using McNemar's test Kappa results were as 0.610, 0.181, 0.610, 0.708 for culture, HpIgG, Rapid Urease Test and HpSA, respectively. CONCLUSIONS: HpSA is a cheap, effective method for the diagnosis of H. pylori infection in the Turkish population.