Inclusion Criteria:  Patients: -  Male and female patients aged ≥ 18 years. Specimens from patients undergoing tissue sampling, stool, and blood to rule out Helicobacter pylori infection Written informed consent from patients.  Volunteer subjects: -  Male and female (non-pregnant) volunteers between the ages of 18-65 years. Written informed consent from volunteers. No acute medical conditions No regular medication use, and no antibiotic use in the last 4 weeks.  Exclusion Criteria:  Patients: -  Minor patients Patients not capable of giving consent Samples without sufficient residual material after standard diagnostic procedures Samples from patients who have not given consent for testing  Volunteer subjects: -  Subjects not capable of giving consent Subjects with acute illnesses Subjects older than 65 or younger than 18 years of age. Pregnant women