Comparison of invasive methods and two different stool antigen tests for diagnosis of H pylori infection in patients with gastric bleeding

AIM： To compare two different H pylori stool antigen tests as noninvasive diagnostic methods. METHODS： The study population consisted of 22 upper gastrointestinal system bleeding patients. Urea breath test （UBT）, rapid urease test （RUT） and histopathological examination were applied to all patients. Stool specimens from these patients were examined by rapid STPIP!HpSA and one step simple H pylori antigen cassette test for the detection of Hpylori antigens. RESULTS： For these 22 patients, 15 （68.2%） were diagnosed as positive and seven （31.8%） were diagnosed negative for H pylori infection by the gold standard methods. Whereas 10 （45.5%） were positive and 12 （54.5%） were diagnosed negative by the rapid STPIP!HpSA test. The sensitivity, specificity, positive and negative predictive values were 60%, 86%, 90% and 50%, respectively. When compared to the gold standard methods, these differences were not significant. However, six patients （27.3%） were positive, and 16 （72.7%） were negative by the simple H pylori stool antigen cassette test. The sensitivity, specificity, positive and negative predictive values were 33%, 86%, 83% and 38%, respectively. Compared to the gold standard methods, the simple H pylori stool antigen cassette test results were significantly different （P = 0.012）. CONCLUSION： Rapid STRIP!HpSA test could be used as a routine diagnostic tool in the microbiology laboratory for assessing clinical significance and eradication control of H pylori in upper gastrointestinal system bleeding patients.

Comparison of a monoclonal antigen stool test (Hp StAR) with the ^(13)C-urea breath test in monitoring Helicobacter pylori eradication therapy

AIM： To evaluate the agreement between a mAb-based stool test （HP STAR） and the urea breath test （UBT） in monitoring （H pylon） infection after eradication therapy. METHODS： Patients with discordant results on UBT and Hp STAR underwent endoscopy with biopsies for rapid urease test, culture, and histology to confirm H pylori status. RESULTS： Among 250 patients （50±14 years）, 240 （96.0%） had concordant UBT and Hp STAR tests with a significant correlation between DOB and A values （R = 0.87; P〈0.0001）. The remaining 10 （4.0%） patients had discordant tests （positive Hp STAR and negative UBT） with the Hp STAR inaccurate in five cases （false positive） and UBT inaccurate in the other five cases （false negative）. The “maximal expected” sensitivity, specificity, ＋PV, -PV, ＋LR, and -LR were 91%, 100%, 100%, 97.4%, ∞, and 8.2 respectively, for the UBT, and 100%, 97.4%, 91%, 100%, 38.8, and 0, respectively, for the Hp STAR. Overall accuracy for both tests was 98%. CONCLUSION： Both the UBT and the Hp StAR are equally accurate in monitoring H pylori infection. Nowadays, the choice of the “best” non-invasive H pylori test in the post-treatment setting should be done not only in terms of diagnostic accuracy but also in view of cost and local facilities.

Retrospective analysis of discordant results between histology and other clinical diagnostic tests on helicobacter pylori infection

BACKGROUND A reliable test is essential for diagnosing Helicobacter pylori(H.pylori)infection,and crucial for managing H.pylori-related diseases.Serving as an excellent method for detecting H.pylori infection,histologic examination is a test that clinicians heavily rely on,especially when complemented with immunohistochemistry(IHC).Additionally,other diagnostic tests for H.pylori,such as the rapid urease test(CLO test)and stool antigen test(SA),are also highly sensitive and specific.Typically,the results of histology and other tests align with each other.However,on rare occasions,discrepancy between histopathology and other H.pylori diagnostic tests occurs.AIM To investigate the discordance between histology and other H.pylori tests,the underlying causes,and the impact on clinical management.METHODS Pathology reports of gastric biopsies were retrieved spanning August 2013 and July 2018.Reports were included in the study only if there were other H.pylori tests within seven days of the biopsy.These additional tests include CLO test,SA,and H.pylori culture.Concordance between histopathology and other tests was determined based on the consistency of results.In instances where histology results were negative while other tests were positive,the slides were retrieved for re-assessment,and the clinical chart was reviewed.RESULTS Of 1396 pathology reports were identified,each accompanied by one additional H.pylori test.The concordance rates in detecting H.pylori infection between biopsy and other tests did not exhibit significant differences based on the number of biopsy fragments.117 discrepant cases were identified.Only 20 cases(9 with CLO test and 11 with SA)had negative biopsy but positive results in other tests.Four cases initially stained with Warthin-Starry turned out to be positive for H.pylori with subsequent IHC staining.Among the remaining 16 true discrepant cases,10 patients were on proton pump inhibitors before the biopsy and/or other tests.Most patients underwent treatment,except for two who were untreated,and two patients who were lost to follow-up.CONCLUSION There are rare discrepant cases with negative biopsy but positive in SA or CLO test.Various factors may contribute to this inconsistency.Most patients in such cases had undergone treatment.

Helicobacter pylori infection- recent developments in diagnosis

Considering the recommended indications for Helicobacter pylori(H.pylori)eradication therapy and the broad spectrum of available diagnostic methods,a reliable diagnosis is mandatory both before and after eradication therapy.Only highly accurate tests should be used in clinical practice,and the sensitivity and specificity of an adequate test should exceed 90%.The choice of tests should take into account clinical circumstances,the likelihood ratio of positive and negative tests,the cost-effectiveness of the testing strategy and the availability of the tests.This review concerns some of the most recent developments in diagnostic methods of H.pylori infection,namely the contribution of novel endoscopic evaluation methodologies for the diagnosis of H.pylori infection,such as magnifying endoscopy techniques and chromoendoscopy.In addition,the diagnostic contribution of histology and the urea breath test was explored recently in specific clinical settings and patient groups.Recent studies recommend enhancing the number of biopsy fragments for the rapid urease test.Bacterial culture from the gastric biopsy is the gold standard technique,and is recommended for antibiotic susceptibility test.Serology is used for initial screening and the stool antigen test is particularly used when the urea breath test is not available,while molecular methods have gained attention mostly for detecting antibiotic resistance.