Prospective, study comparing the accuracy of two different stool antigen tests (Premier Platinum HpSA and novel ImmunoCard STAT! rapid test) for the diagnosis of Helicobacter pylori infection.

Background: At present only monoclonal EIA (enzyme-immunoassay) stool antigen-tests have obtained optimal accuracy in the diagnosis of Helicobacter pylori. Our aim was to evaluate the accuracy of two stool antigen-tests, the validated Premier Platinum HpSA PLUS (EIA test) and the newly available ImmunoCard STAT! HpSA HD (rapid test) for the initial diagnosis and the confirmation of eradication of H. pylori infection.
Patients and Methods: Patients with indication of H. pylori diagnosis, or confirmation after treatment were included. Data were coded to protect personal data and ensure blindness between tests. Accuracy was considered as coincident diagnosis with the gold standard ( ¹³ C-urea breath test, UBT). The EIA was used as a bench standard. All stool tests were performed in duplicate.
Results: 264 patients completed the protocol (100 naïve, 164 post-eradication). Average age was 52 years, 61% women, 11% ulcer. Positive diagnoses by UBT were 41% for naïve and 17% for post-eradication. Overall ImmunoCard and EIA accuracies were respectively 91% (95%C.I.=88-94%) and 89% (86-93%), sensitivities 72% (67-78%) and 72% (67-78%), and specificities 98% (96-100%), and 95% (92-97%). Concordance between ImmunoCard and EIA was 95% (93-98%).
Discussion: Our results indicate that the newly available ImmunoCard rapid stool antigen-test achieves 90% accuracy, with high specificity but suboptimal sensitivity. The ImmunoCard attained equivalent accuracies as the EIA bench standard, with 95% concordance.
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