[Testing a new in-office test for determination of faecal Helicobacter pylori antigen]

To date, the search for an in-office reliable test for Helicobacter pylori infection has been unsuccessful. The aim of the present study was to evaluate a new immunocromatographic in-office test using monoclonal antibodies to determine the presence of Helicobacter pylori antigen in faeces (Stick H. pyl, Operon S.A. Zaragoza). We compared its reliability and reproducibility to the currently available test (HpSA, EIA, Premier Platinum HpSA, Meridian Diagnosis Inc, Cincinnati, Ohio).

71 consecutive dyspeptic patients were enrolled. Helicobacter pylori status was determined by rapid urease test and Giemsa stain of antral biopsy. Patients with a positive result in the two tests were considered as infected and those with a negative result in both tests were regarded as not infected. Faecal Helicobacter pylori antigen was tested twice by means of HpSA. Four consecutive determinations of Stick H. pyl were also performed. We calculated sensitivity, specificity and positive and negative predictive values of each determination. Concordance between determinations was estimated by the kappa statistics.

Forty-eight of 68 patients were infected by Helicobacter pylori. Sensitivity, specificity and positive and negative predictive values were 89-96%, 60-70% 85-88% and 74-87%, respectively, for Stick H. pyl and 70-75%, 60-85%, 85-92% and 55-80%, respectively, for HpSA. Correlation coefficients were 0.82-0.93 for Stick H. pyl and 0.57 for HpSA.

The new Stick H. pyl test shows excellent sensitivity and reproducibility for diagnosis of H. pylori infection. Its reliability appears to be far better than that of HpSA.