ABSTRACT
Objective To investigate the efficacy of the four commonly used diagnostic methods in infection of Helicobacter pylori ( H. pylori ) . Methods The study included 133 patients with upper gastrointestinal symptoms. Three fresh gastric biopsy were extracted from the lesser curvature of antrum when patients accepting gastroscopy,for the rapid urease test( RUT) test strip, RUT gel method, and histological examination, respectively.14C?urease breath test(14C?UBT) was carried out 1 hour after the procedure. The result of histological examination was served as the golden reference.Any two tests positive were served as the relative golden reference. The diagnostic accuracy of the four methods and the consistence with golden reference and relative golden reference was evaluated. Results The positive results were obtained in 111 cases by RUT test strip,76 by RUT gel method, 70 by 14C?UBT,and 62 by Warthin—Starry stain. With Warthin—Starry positive as the golden reference, the finding of RUT test strip was poorly consistent with the result of Warthin—Starry(Kappa=0?295).However, the findings of RUT gel method and 14C?UBT were highly consistent with the result of Warthin—Starry( Kappa=0?672,0?670) . Because of the poor specificity of RUT test strip, any two positive tests from Warthin—Starry,RUT gel method and 14 C?UBT were used as the relative golden reference to evaluate the diagnostic accuracy. The findings of Warthin—Starry and 14 C?UBT were perfectly consistent with the golden reference( Kappa=0?821,0?850) , and the finding of RUT gel method was highly consistent with the golden reference(Kappa=0?763). However, the finding of RUT test strip was poorly consistent with golden reference(Kappa=0?280).When the delta cutoff value for the UBT was calculated as a standard value(DMP≥100),the area under the ROC curve was 0?932 (0?884?0?979) , and the sensitivity, specificity and accuracy of 14 C?UBT were 100?0%, 86?3% and 92?5%, respectively.When the delta cutoff value for the UBT was recalculated as a new value(DMP≥166),the area under the ROC curve increased to 0?949(0?906?0?992).With the golden reference as the evaluation, the sensitivity, specificity and accuracy of UBT test were 96?7%, 93?2% and 94?7%, respectively. Conclusion RUT test strip shows low accuracy; RUT gel method,UBT and histological examination have high accuracy and similar efficacy. When the delta cutoff value for the test is recalculated as DMP≥166, the accuracy of the test can be improved.
ABSTRACT
As the practicing physicians start treating all dyspeptic symptoms as peptic ulcer disease and some patients are treated for Helicobacter pylori infection without confirmation of infection. Hence, a simple and convenient test to identify the H. pylori infection is essential in the management of all dyspepsia. Serological test is a noninvasive test and result can be obtained within short time and treatment can be started early. Methods: A total of 86 outpatients with dyspeptic symptoms underwent both serological test and endoscopy and biopsy for H. pylori infection. Serological testing for H. pylori is based on the immunoglobulin G antibody to H. pylori infection. Results: Of 86 patients, 79 patients’ biopsy were positive for H. pylori and 77 patients were positive by serology. Of them, 75 were both positive for H. pylori by biopsy and also by serology. Those 7, who are negative for histology is also negative for serology. Comparing endoscopic biopsy with serology, the specificity, sensitivity are 97.5, 98 for serology. Conclusions: Serological tests assess the global presence of H. pylori in the stomach even when the bacteria are irregularly distributed on the gastric mucosa. Serology testing is cheaper and more convenient, and thus should be preferred in situations where the additional information yielded by an endoscopy is not needed.
ABSTRACT
Objective To investigate the status of Helicobacter pylori(H.pylori) infection and the accuracy of the two commonly used diagnostic methods, the 14 C urease breath test( 14 C UBT) and the rapid urease test(RUT) in patients with partial gastrectomy due to peptic ulcer or gastric cancer. Methods Culture, histology, RUT, combined with 14 C UBT, were carried out to diagnose the H. pylori infection in patients with partial gastrectomy. The Giemsa staining and H.pylori culture served as the ‘golden reference’ in evaluating the diagnostic accuracy of the RUT and 14 C UBT. The prevalence of H.pylori infection of patients with partial gastrectomy was determined with the dyspeptic controls without surgery. Results 37 patients (17 Billroth Ⅰ resection, 20 Billroth Ⅱ resection) were included in the study. The overall prevalence in the Giemsa staining and culture proved as H.pylori infection was 29.7%, and no statistical difference was seen between patients will Billroth Ⅰ(29.4%) and Billroth Ⅱ(30.0%) resections. The sensitivity of the RUT was 72.7%, the specificity was 57.7%, and the overall accuracy was 62.2%. The sensitivity of the 14 C UBT was 63.6%, the specificity was 100.0%. The negative predictive value was 86.7%, and the overall accuracy was 89.2%. The total prevalence of H.pylori infection in the controls was 71.4%. Conclusion Prevalence of H.pylori infection in patients with partial gastric resection is low. The two diagnostic methods, 14 C UBT and RUT, cannot be recommended as accurate diagnostic tools for H.pylori infection in patients after partial gastrectomy due to low specificity and low sensitivity, respectively.