Evaluation of handling methods in the histological diagnosis of Helicobacter pylori: the effect of filter paper.

Objectives: Few studies have evaluated the handling methods used in the histological diagnosis of Helicobacter pylori. Filter paper has conventionally been used as a receptacle for the biopsy specimen before fixation. The aim of this study was to determine the presence of any effect caused by the use of filter paper.

Methods: The study population consisted of 104 consecutive patients undergoing endoscopic examination. Two antral biopsy specimens from the same area were obtained from each patient. One specimen was put onto a piece of filter paper, and the other into a plastic case. The specimens were fixed overnight in buffered formalin, embedded in paraffin, sectioned, and stained with hematoxylin and eosin and Giemsa. A direct smear was also prepared from 77 patients by vigorously rubbing the filter paper on a glass slide and staining it with Giemsa.

Results: The detection rate of H. pylori was 47.1% (49 of 104) for the filter paper method, 56.7% (59 of 104) for the plastic case method, and 57.7% (60 of 104) for either of the two methods. Of the 60 positive patients, 11 filter paper specimens were negative, whereas only one plastic case specimen was negative. Statistical analysis revealed a significant difference between the two groups (p < 0.01). On the amount of H. pylori, the filter paper method showed a significantly lower grade than the plastic case method (p < 0.05). In the Giemsa-stained smears, H. pylori was identified in 17 (22.1%) of the 77 patients studied.

Conclusions: Use of filter paper may decrease the sensitivity for detection of H. pylori infection. We recommend not using filter paper in the histological diagnosis of H. pylori.