Comparison of special stains (Giemsa stain and Modified Toluidine Blue stain) with immunohistochemistry as gold standard for the detection of H. pylori in gastric biopsies

Background and study aims: Helicobacter pylori (H. pylori) has been extensively implicated in the etiology and pathogenesis of gastric ulcers and carcinomas, which has necessitated its efficient and cost-effective identification in gastric biopsy samples. We have sought to compare various staining methods, namely, Hematoxylin and Eosin (H&E), Giemsa, and Modified Toluidine Blue (MTB), with immunohistochemistry (IHC; gold standard) in terms of efficacy, staining costs, and duration of performing the stains in settings with limited resources.

Patients and methods: Gastric biopsy specimens of 50 patients who presented with gastritis symptoms were stained with H&E, Giemsa, MTB, and IHC. The sensitivity, specificity, positive/negative predictive values, and the receiver operating characteristic curve were calculated for each stain.

Results: In all, 32 cases of 50 were positive for H. pylori on IHC. The specificity for both H&E and Giemsa was 88.8%, whereas it was lower for MTB (83.3%). The sensitivity of H&E was much lower (46.8%) compared with the Other stains (90.6% Giemsa, 93.7% MTB). The most inexpensive and time-consuming stain was H&E followed by MTB and Giemsa.

Conclusion: When H&E is used alone for H. pylori detection, a significant number of cases may be overlooked, especially mild inflammatory cases and when coccoid forms of the bacteria are present. This study proposes the use of either Giemsa or MTB as reliable alternatives for IHC in resource-limited settings to combat the high prevalence of H. pylori in the developing world.

Azure stains; Gastric biopsy; Helicobacter pylori; Immunohistochemistry.