Detection of Helicobacter pylori in Gastric Biopsy Specimens by Polymerase Chain Reaction

Kim, Gwang Ha; Ok, Chang Min; Yu, Young Il; Huh, Jung; Choi, Seong Ho; Song, Chul Soo; Song, Geun Am; Cho, Mong; Yang, Ung Suk; Moon, Han Kyu

Abstract

OBJECTIVE
Helicobacter pylori (H. pylori) has been implicated in the pathogenesis of chronic gastritis, gastric ulcer, duodenal ulcer and gastric cancer. Histological examination and culture are considered to be the most specific tests, and rapid urease test and serological test are rapid but less specific tests. 'I he aim of this study was to investigate the efficiency of the polymerase chain reaction (PCR) assay as a procedure for the diagnosis of H, pylori infection in gastric biopsy specimens.
METHODS
Biopsy specimens were obtained from the gastric antrum within 2cm from the pyloric channel of 42 patients during endoscopy and submitted for the histological examination, CLO test, and PCR assay. At the same time, another biopsy specimens were obtained from the lesion for the diagnosis of the diseases. Also, blood was sampled for the measure of the value of IgM and IgG.
RESULTS
As the result of the histopathological examination, chronic gastritis was diagnosed in 13 patients, gastric ulcer in 11, duodenal ulcer in H, and gastric cancer in 10. By the histological examination of the antrum, H, pylori were found in 77% of chronic gastritis, 55% of gastric ulcer, 75% of duodenal ulcer, and 40% of gastric cancer. As a whole, the bacteria was identified in 62%, 60%, 88%, 90%, 69% of patients by histological test, CLD test, IgM, IgG, and P(;R respectively. The gold standard we used for the presence of bacteria was histological examination. Sensitivity, specificity, positive predictive value, ancl negative predictive value for PCR assay were 92%, 69%, 83% and 85% respectively. The results of other test were as follows. CLO test: 89%, 88%, 92%, 82%, IgM:92%, 19%, 65%, 60%, IgG:100%, 25%, 68%, 100%.
CONCLUSION
CR is a very sensitive but some- what less specific test for the detection of H. pylori. This is mainly due to the contamination of H. pylori during endoscopy and biopsy. So, minimization of the contamination would make PCR clinically useful test.