Evaluation of 3 different tests for the detection of stool antigens to confirm Helicobacter pylori eradication after treatment. A pilot study

Abstract

Introduction: Recently, several new diagnostic methods aimed to detect Helicobacter pylori stool antigens have been developed. Our aim was to evaluate the accuracy of 3 different stool tests to confirm H. pylori eradication.

Patients and methods: Twenty-six patients received H. pylori eradication treatment. Eradication was confirmed with 13C-urea breath test 6-8 weeks later, when stool samples were analyzed by polyclonal (Premier-Platinum-HpSATM), monoclonal (Amplified-IDEIATM-HpStARTM), and rapid test (ImmunoCard-STAT-HpSATM).

Results: H. pylori was eradicated in 85% of the cases. Sensitivity, specificity, positive predictive value and negative predictive value with the polyclonal test were: 25%, 91%, 33% and 87%. Corresponding results with the monoclonal test, using the cut-off point recommended by the manufacturer, were 100%, 46%, 25% and 100%. However, the best cut-off point in our study had 100% sensitivity and 91% specificity. The area under ROC curve for the polyclonal and the monoclonal tests was 0.65 and 0.95. Diagnostic accuracy with the rapid test was 75%, 90%, 60% and 95%.

Conclusion: Neither the polyclonal stool antigen test nor the rapid stool antigen test can be recommended to confirm H. pylori eradication after treatment. The monoclonal test has better diagnostic accuracy, although more studies are necessary to definitively recommend its use for the confirmation of H. pylori eradication success.