Diagnosis of Helicobacter Pylori Infection Using Polymerase Chain Reaction in Gastric Biopsy Specimens

Kim, Doe Young

Abstract

BACKGROUND/AIMS: Helicobacter pylori infection is now recognized as a cause of chronic gastritis, peptic ulcer disease and is also a major risk factor for development of gastric carcinorna and gastric lymphorna. Several diagnostic methods of H. pylori infection, such as histopathology, Giemsa stain, culture, CLO test, urea breath test and serologic test have been used, Recently, the polymerase chain reaction(PCR) assay has provided a means of rapid and sensitive detection of FI. pylori. This study aimed to evaluate the PCR assay for the diagnosis of H. pylori infection.
METHODS
I compared the PCR assay using the ureC gene specific for H. pylori with other te:sts in gastric biopsy specimens from 118 patients and evaluated the positive rates of H. pylori according to gastroduodenal diseases.
RESULTS
Ninty-nine out of 118(84%) were PCR positive a,nd 87 out of 118(74%) were CLO test positive. Thirty four out of 81(42%) patients were culture: positive and 43 out of 64(67%) were H & E stain positive. In seventy-six out of 118 patients (64%) PCR was concordant with CLO test. Diagnostic sensitivity, specificity, positive predictive value and negative predictive value of PCR were 96%, 25%, 79% and 57% respectively, those of CLO test were 100%, 94%, 98% and 100% respectively, those of culture were 77%, 100%, 100% and 62% respectively, and those of H k E stain were 94%, 93%, 97% and 87% respectively, The positive rates of H. pylori using PCR were 90%, 87%, 69%, 92%, 64% and 88% in active stage, healing stage, scar stage of duodenal ulcer, gastric ulcer, chronic gastritis and gastric cancer patients, respectively.
CONCLUSIONS
These findings suggest that the PCR assay using the ureC gene in gastric biopsy tissue is more sensitive but less specific than culture and we should try to minimize the cases of false positive with all efforts if it is used for the diagnosis of H. pylori infection.