Current Methods Used for the Diagnosis of Helicobacter pylori Infection

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.