Nested polymerase chain reaction for detection of Helicobacter pylori in gastric biopsy specimens.

Sensitivity and specificity are important for tests used to defect Helicobacter pylori infection from gastric biopsy specimens. Molecular methods, such as PCR and nested PCR, are sensitive methods for H. pylori detection. The objective of this study was to evaluate the performance of PCR and nested PCR compared to culture, the rapid urease test (RUT) and histology for the diagnosis of H. pylori in 130 gastric biopsy specimens from symptomatic dyspeptic patients. Sensitivity and specificity with PCR were 91 and 100% and with nested PCR were 95 and 97%, respectively. H. pylori was detected by PCR and nested PCR at levels as low as 125 fg (70 cells) and 25 fg (14 cells), respectively. These results suggest nested PCR is a highly sensitive direct method to detect H. pylori infection from biopsy specimens.