Histological identification of Helicobacter pylori: comparison of stainingmethods

Aim-To determine whether two recently described staining methods (the modif ied McMullen's and the Helicobacter pylori silver stain HpSS methods) used for the histological identification of H pylori organisms are superior to t wo established techniques (the modified Giemsa and anti-H pylori antibody i mmunostain) in terms of availability, reproducibility rapidity, sensitivity , and cost. Methods-Histological sections from 63 paired gastric biopsies from adult pa tients previously investigated for dyspepsia were stained with the four met hods and these were assessed blindly and independently by two observers. Of the 63 patients, 30 were originally negative in all tests for H pylori inf ection, 30 were positive, and the remaining three cases had discordant resu lts using a combination of five tests (rapid biopsy urease test, urea breat h test, culture, serology, and histology). Results-Interobserver agreement was best with the antibody method (98%), fo llowed by the McMullen's (90%),Giemsa (87%), and HpSS (85%). Of the 60 "gol d standard" positive and negative cases, 30 were positive by the modified G iemsa stain? 29 by the McMullen's method, 29 by HpSS, and 30 by the antibod y stain. However, there were two false positives with the HpSS method. The modified Giemsa is the cheapest and easiest to perform technically. Conclusions-When H pylori are present, careful examination will almost alwa ys reveal them, whichever of these stains is used. However, the modified Gi emsa stain is the method of choice because it is sensitive, cheap, easy to perform, and reproducible.