Sensitivity and Specificity of the Modified Helicobacter Test INFAI

Study to confirm the sensitivity of the C\^13-UBT using the new test meal for H. Pylori in patients with dyspepsia and GERD taking PPI

Secondary objectives : to compare the sensitivity and specificity of the C\^13-UBT using the new test meal and standard test meal for H.Pylori in patients with dyspepsia and GERD taking PPI.

to complete the results of the Helicbacter test INFAI using new test meal for H.Pylori in patients with dyspepsia and GERD taking PPI with :

* Histology score for H.Pylori in antrum an corpus using the updated Sydney System
* Sex,
* Age,
* Body Mass Index (BMI)

Helicobacter pylori (H. pylori) infection can be diagnosed by invasive (i.e., endoscopy and biopsy) and non-invasive techniques . The most accurate non-invasive tests for diagnosing active H. pylori are the 13C-urea breath test and the stool antigen test3 Several guidelines for the management of dyspeptic patients in primary care settings recommend the use of non-invasive tests for H. pylori in the initial management of dyspeptic patients (test and treat strategy)3 . This strategy has been tested in a number of clinical settings and has been shown to be effective from both a clinical and a cost perspective The urea breath test (UBT) and the stool antigen test are very sensitive and specific except in patients taking proton pump inhibitors (PPI) 678 In patients taking PPI, a positive test remains reliable for the detection of H. pylori but the number of false negative tests rises dramatically reducing the sensitivity of these tests. PPI are widely available and are over-thecounter agents in some countries (e.g. USA, Sweden). Clinicians are frequently confronted with making a diagnosis of H. pylori infection in patients who may knowingly or unknowingly be taking PPI. Currently available breath and stool tests are reliable 12 - 14 days after discontinuation of the PPI. This results in the cost and inconvenience of another visit and the possibility of symptoms in some patients when the PPI is withdrawn.

Although the exact mechanism by which acid inhibition causes a false negative reaction is unclear, some studies have suggested that acidification of the stomach may reverse the abnormality Results have been inconsistent, however, and how to acidify the stomach and to what extent this should be done is unclear. Standardised test meals are routinely administered with the breath test substrate.

The aim of this study is to assess the sensitivity and specificity of the 13C-urea breath test administered with the new test meal in patients with dyspepsia and GERD taking PPI.

Eligibility Criteria:
Inclusion Criteria:

* Male and female patients of at least 18 years of age.
* All acid-related disorders requiring long-term PPI treatment including functional dyspepsia according Rome IV classification.
* Positive or negative standard 13C-UBT at screening.
* Diagnosis of H. pylori infection confirmed or excluded by combination of culture , histology and rapid\*\* urease test (PyloriTek@, Serim Research Corp., Elkhart, IN, USA) on samples obtained by endoscopy:
* True positive if culture positive and/or positive histology in combination with positive urease test.
* True negative if culture is negative and if histology and/or urease test is negative. True negative if culture not evaluable and both histology and urease test are negative.
* Culture will be based on biopsies from antrum and corpus. Two biopsies will be taken from antrum and corpus for histology. Rapid urease test will be performed on the samples of antrum and corpus. Written informed consent of the patient.

Exclusion Criteria:

* Previous H. pylori eradication therapy.
* Intake of PPI off 14 days, 1-12 receptor antagonists 1 day, NSAlDs, antibiotics, antisecretory drugs, bismuth compounds, or sucralfate in the 4 weeks prior to enrolment.
* Manifest coagulopathy or any other disorder according to which endoscopy and/or biopsies are contraindicated.
* Participation in a clinical trial with another not approved drug within 30 days before entering the study and/or previous participation in this study.
* Pregnancy