pylori should receive eradication H 89 cost therapy.2 Diagnosis of H. pylori infection has become increasingly important for successful eradication. The 13C-urea breath test (UBT) has been considered to be the most reliable non-invasive test for the diagnosis of H. pylori infection, with an overall accuracy approaching 95% in both untreated

and treated patients.3 Therefore, UBT is now commonly used to test the results of eradication therapy, but the cost of UBT is relatively high and this test has several limitations.4,5 Monoclonal antibody (MAb)-based stool antigen tests have fewer restrictions because they do not require fasting and the tests are not influenced by the urease activity of H. heilmannii or oral bacteria. In addition, sampling errors in stool antigen

tests would not be frequent because the antigen is equally distributed throughout the feces by enterokinesis. As non-invasive diagnostic tests, several stool antigen tests using monoclonal antibodies have been established. These tests have been shown to have high sensitivity and specificity comparable with those of UBT.6,7 The new Japanese guidelines also recommend stool antigen tests using monoclonal antibodies to examine the results of eradication therapy.2 Two types of stool antigen tests have been widely used for the diagnosis of H. pylori infection: an enzyme immunoassay (EIA) and an assay based on immunochromatography. We have established three MAbs with high specificity for the native H. pylori catalase antigen.8,9 Using one of these Enzalutamide MAbs (21G2), we developed a single-step direct sandwich EIA: Testmate Pylori Antigen EIA (TPAg EIA), and an immunochromatographic test: Testmate Rapid Pylori Antigen (Rapid TPAg). Several studies in the USA and Japan have verified the accuracy

and usefulness of TPAg EIA and Rapid TPAg in confirming the results Thiamine-diphosphate kinase of eradication therapy.10–14 Although there is increasing clinical evidence, basic studies of the Testmate kits have been done. In the present study, we examined the characteristics and stability of TPAg EIA and Rapid TPAg using human fecal samples, H. pylori clinical isolates, other Helicobacter spp. and intestinal bacteria. Plastic 96-well EIA microtiter plates were coated with MAb 21G2.8 Peroxidase-labeled MAb 21G2 was conjugated with peroxidase-N-succinimidyl ester according to the manufacturer’s instructions (LK11-10 Peroxidase Labeling Kit-NH2 Unit: Dojindo Molecular Technologies, Inc., Tokyo, Japan). We used phosphate buffered saline (PBS; Dulbecco’s PBS[-]) containing 0.05% Tween 20 as a washing buffer, PBS containing 0.05% Tween 20 plus 5% BSA, Fr V (Serologicals Proteins Inc., Kankakee, IL, USA) as a diluent buffer, 3,3′,5,5′-tetramethylbenzidine (TMB: BioFX, Owings Mills, MD, USA) as the substrate solution, and 1N H2SO4 as the stop reagent for the reaction. TPAg EIA test was carried out according to a previously described procedure.9 Briefly, H.