Comparison of stool enzyme immunoassay and immunochromatographic method for detecting Helicobacter pylori antigens before and after eradication

The objective of this study is to compare the performance of enzyme immunoassay (Premier Platinum HpSA) and immunochromatographic method (ImmunoCard HpSA STAT) in detecting stool Helicobacter pylori antigen before and after eradication therapy. Two hundred forty dyspeptic patients (143 men and 97 women; mean age, 53.2 years old; range, 19–79 years old) volunteered to participate in this study. Those who delivered improper stool samples, including diarrhea, inadequate amount, or delayed delivery after collection, were excluded. All of the participants received endoscopy, biopsy-based tests, and noninvasive tests, including 13C-urea breath test (13C-UBT) and 2 stool antigen tests. Fifty-eight patients completed all the above tests before and after eradication therapy, and each contributed to 2 person-times. In total, there were 176 person-times in the preeradication group and 100 in the posteradication group that were analyzed for comparison. Follow-up endoscopic examinations were done 2 to 4 months after completion of eradication therapy, and stool samples were collected within 3 days after endoscopy. Positive H. pylori infection was established when either culture was positive or any 2 of the histology, rapid urease test, and UBT were positive. In the preeradication group (n = 176), 99 (56.3%) were H. pylori positive and 77 were Hp negative. In the posteradication group (n = 100), the treatment was successful in 67 (67.0%) of them. In the preeradication group, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were 95.2%, 87.0%, 90.4%, 93.1%, and 91.5%, respectively, for ImmunoCard HpSA STAT, and 83.8%, 90.9%, 92.2%, 81.4%, and 86.9%, respectively, for Premier Platinum HpSA. In the posteradication group, the sensitivity, specificity, PPV, NPV, and accuracy were 100%, 91.0%, 84.6%, 100%, and 94.0%, respectively, for ImmunoCard HpSA STAT, and 84.9%, 92.5%, 84.8%, 92.5%, and 90.0%, respectively, for Premier Platinum HpSA. There were no statistically significant differences between these 2 stool tests. ImmunoCard HpSA STAT is a rapid, simple, and accurate in-clinic test for preeradication diagnosis of H. pylori and posteradication follow-up.