Spraying of phenol red dye as a screening test for Helicobacter pylori infection in surgically resected stomach specimens.

BACKGROUND

Endoscopic spraying of phenol red dye and urea (phenol red test) has recently been used to assess the distribution of Helicobacter pylori in the gastric mucosa. We examined whether the phenol red test could be used to detect H. pylori in surgically resected stomachs.

METHODS

A total of 82 surgically resected stomachs, obtained from 82 patients (mean age, 60.1 years; range, 33-84 years) with early gastric carcinomas were examined. Phenol red solution and urea were sprayed over the entire mucosa of each resected stomach. A color change from yellow to red was considered as a positive reaction for H. pylori. Gastric mucosal specimens taken from positively stained and negatively stained areas on the phenol red test were then examined immunohistochemically to determine the degree of H. pylori colonization.

RESULTS

Diffusely positive reactions were seen in 16 resected stomachs (19%), and regionally positive reactions were seen in 36 (44%). The other 30 stomachs (37%) showed no color change (negative reaction). H. pylori was detected immunohistochemically significantly more frequently in positively stained than in negatively stained areas ( P << 0.0001). Specificity, sensitivity, and predictive values for positive and negative results of the phenol red test, determined on the basis of H. pylori immunostaining, were 100%, 74.3%, 100%, and 72.7%, respectively.

CONCLUSIONS

The phenol red test is a specific, relatively sensitive, rapid, easy-to-use, and repeatable method that can be used to diagnose H. pylori infection in surgically resected material. It enables pathologists as well as gastroenterologists with no microbiological expertise to easily diagnose H. pylori infection.