A number of methods have been proposed to diagnose Helicobacter pylori
infection. In this chapter, each method is presented and the critical aspects are highlighted.
It is common practice to distinguish the methods which necessitate an endoscopy and
obtention of biopsy specimens, the so-called invasive methods, from the methods which are
performed on blood, stools, air, etc., the so-called non-invasive methods. Among the
invasive methods, histology is probably the most commonly used worldwide, and has
been recently completed by the use of the OLGA or OLGIM system to evaluate the
gastric cancer risk. Culture is demanding for transport but there has been a renewed
interest because of the increase in H. pylori antimicrobial resistance. The rapid urease
test, while not as sensitive, has the great advantage of providing a quick result allowing
to prescribe immediately a treatment. Molecular methods are developing, especially
real-time PCR for which kits are now available, detecting H. pylori and its resistance to
clarithromycin, and allowing standardization. An advantage of this method is the
possibility to apply it to stools, rendering it non-invasive. However, at this stage, DNA
extraction is still a problem. The best method to be used in such specimens is a stool
antigen test using an ELISA with monoclonal antibodies. However, many still prefer the
urea breath test which has become a standard in the field. Finally ELISA serological
tests have also experienced a revival since they are the only tests to be used on patients
taking proton pump inhibitors, nowadays a common situation.
Keywords: Histology, culture, rapid urease test, standard PCR, real-time PCR,
urea breath test, stool antigen test, serology, ELISA, immunoblot, pepsinogen,
sensitivity, specificity, OLGA, Helicobacter heilmannii.
