HpSA: Assessment of a new non-invasive diagnostic assay for Helicobacter pylori infection in an Irish population

Background: The diagnosis of Helicobacter pylori is an essential element in the management of many common gastrointestinal pathologies. Previously diagnosis was dependent on the availability of endoscopic biopsy samples. The advent of non invasive assays such as the C13Urea breath test and Elisa serology have enabled diagnosis, and treatment to be undertaken in the primary care setting. The isolation of Helicobacter pylori antigen from stool has led to the development of a new non-invasive test. Aim: A prospective study was designed to assess and compare the performance of Premier Platinum HpSA with current gold standard tests. Methods: Consecutive patients undergoing a gastroscopy for investigation of dyspepsia at the Meath and Adelaide hospitals were enrolled. At endoscopy gastric biopsies were taken for histology, microbiology and rapid urease testing. In addition all subjects had C13UBT, serology and stool tests performed. Individuals who were H. pylori positive received standard proton pump inhibitor based triple therapy. Following treatment all tests, apart from serology were repeated. Results: 54 patients were enrolled, 46 per cent were H. pylori positive. HpSA had a sensitivity and specificity and positive and negative predicted values of 96 per cent, 75 per cent and 80.6 per cent, 75.8 per cent respectively and compared favourably with all other tests. The sensitivity and specificities of the other tests were, histology 79.2 per cent and 100 per cent, culture 68 per cent and 100 per cent, rapid urease test 75 per cent and 100 per cent, serology 75 per cent and 96 per cent and C13 urea breath test 100 per rent and 96.6 per cent. Conclusion: The detection of H. pylori antigen in stool by means of a HpSA assay is a new and effective non-invasive means of diagnosis which can be performed in a routine laboratory setting. It is simple to perform and has possible advantages over other non-invasive tests, detecting actual antigen indicating current active infection.