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 dia gnosis was dependent on the availability of endoscopic biopsy samples. The advent of non invasive assays such as the C13Urea breath test and Elisa ser ology 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 te sting. In addition all subjects had C13UBT, serology and stool tests perfor med. Individuals who were H. pylori positive received standard proton pump inhibitor based triple therapy. Following treatment all tests, apart from s erology were repeated. Results: 54 patients were enrolled, 46 per cent were H. pylori positive. Hp SA had a sensitivity and specificity and positive and negative predicted va lues of 96 per cent, 75 per cent and 80.6 per cent, 75.8 per cent respectiv ely and compared favourably with all other tests. The sensitivity and speci ficities 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 10 0 per cent, serology 75 per cent and 96 per cent and C13 urea breath test 1 00 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 p erformed in a routine laboratory setting. It is simple to perform and has p ossible advantages over other non-invasive tests, detecting actual antigen indicating current active infection.