Evaluation of immunological rapid urease testing for detection of Helicobacter pylori

The aim of this study was to evaluate in clinical specimens the immunologic al rapid urease test (IRUT), a new diagnostic system for detection of Helic obacter pylori which employs a monoclonal antibody against Helicobacter pyl ori urease. Helicobacter pylori urease adsorbed on a solid-phase tip coated with a monoclonal antibody against Helicobacter pylori urease after 15 min of incubation with a gastric mucus sample solution was measured by the pH change of the urea solution inside the tip. The detection limit of Helicoba cter pylori urease using this system was determined and compared with that of a commercially available rapid urease test. Clinical evaluation of the s ystem was performed in 155 patients. The IRUT could detect 0.25 milli-inter national units (mIU) of Helicobacter pylori urease per milliliter in less t han 20 min. If a patient with at least one positive result in a standard te st for Helicobacter pylori was considered to be Helicobacter pylori positiv e, the sensitivity, specificity, positive and negative predictive values of the system were calculated as 95.2%, 98.9%, 98.4% and 96.8%, respectively. However, 10 of 19 Helicobacter pylori-positive patients in whom the pH cha nge was less than 0.1 had negative results in at least one of the standard tests, whereas the IRUT correctly detected Helicobacter pylori in all but 3 of these 19 patients. The IRUT accurately determined the Helicobacter pylo ri status of 75 (98.7%) of 76 patients who had completed treatment, This sy stem has high sensitivity for the detection of Helicobacter pylori, especia lly in patients with low urease activity.