Comparison of polymerase chain reaction and histopathology for the detection of Helicobacter pylori in gastric biopsies.

Using data from a Venezuelan cohort of 1,948 adults, the gastric detection of Helicobacter pylori (H. pylori) by polymerase chain reaction (PCR) of the vacA gene in 1 antral biopsy was compared to the detection of H. pylori by histopathology (hematoxylin-eosin and Giemsa staining) in 5 biopsies (antrum and corpus). Overall, H. pylori was detected in 85% and 95% of the subjects by PCR and histopathology, respectively. When results were analyzed by severity of precancerous lesions, PCR on 1 biopsy detected the bacteria less often than histopathology on 5 biopsies in subjects with normal gastric mucosa and non-atrophic gastritis. However, in subjects with the most severe lesions (intestinal metaplasia type III and dysplasia), PCR on 1 biopsy detected H. pylori as often as histopathology on 5 biopsies, and significantly more often than histopathology on a single biopsy. In conclusion, these findings confirm that histopathology on 5 biopsies is an accurate tool for H. pylori detection in most subjects, compared to the PCR method on 1 biopsy. Nevertheless, the elevated sensitivity of PCR for detecting the bacteria in advanced precancerous lesions, and the possibility to use PCR to distinguish between cagA-positive and cagA-negative strains, makes the PCR technique especially useful in studies of stomach cancer.