Accuracy of Serological And Stool Antigen Tests (non-invasive) for Detection of H. Pylori

Abstract

Background  Helicobacter pylori is a major bacterial causative pathogen of various gasto-doudenal diseases, including chronic gastritis, peptic ulcer disease (PUD), gastric cancer, and mucosa-associated lymphoid tissue lymphoma. The prevalence of H. pylori is about 50% worldwide and could reach more than 70% in developing countries. The aim of the present study was to  evaluate the diagnostic accuracy of both serological and stool antigen tests comparing  with rapid urease test for detection of H. pylori. Methods A 114 patients with gastroduodenal disorders aged 20- 60 years were   recruited in this study. Endoscopic biopsy was obtained from each patient at endoscopic unite in the Al Sader Hospital, Basrah/Iraq. All biopsies were used for rapid urease test. Three ml. of venous blood were collected from each patient and used for serological test.  Stool samples were collected and used for detection of H.pylori Ag. The sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and area of these under receiver operating characteristic (ROC) curve for detection H.pylori Ag/antibody tests were determined using rapid urease test as gold standard method. Result The results showed that the sensitivity of H. pylori Ag and serological test   were (92.6%, 69%), specificity (69.9%, 63.6%), positive predictive value (98.6 %, 82%)  negative predictive value (84%, 45.6%) accuracy (93.8%, 67%) and area under ROS (0.9-0.996, 0.664-0.776) respectively. Conclusion: Stool antigen test is more reliable test for detection H. pylori in comparison to rapid urease test.