Comparative study of microbiological and histopathological techniques usedfor the detection of Helicobacter pylori

This study evaluates the sensitivity, specificity and predictive values of several techniques commonly used for the detection of Helicobacter pylori i n an analysis of 105 biopsy specimens (gastric and duodenal). For comparati ve purposes, the techniques investigated were divided into 2 groups: histop athological and microbiological. The former included hematoxylin-eosin and Giemsa stains, a Gram stain modified for use in tissue, and immunohistochem ical techniques. Microbiological analysis was per formed using culture, the urease test and the conventional Gram stain. The immunohistochemical techn iques proved to be the most sensitive (93%). The modified Gram stain was su fficiently sensitive (92%) and specific (97%) for the detection of the bact erium. When combined with a microbiological technique such as the urease te st, this stain showed increased sensitivity (96%) but its specificity was r educed to 94%. This combination of tests is recommended for the detection o f N. pylori in biopsy specimens since it is easily performed at low cost an d gives excellent results. For economical reasons, it is suggested that the use of immunohistochemical techniques should be restricted to specific cas es.