Methylene blue staining of gastric tissue for the identification of Helicobacter pylori.

This study compared Giemsa (GM) and methylene blue (MB) stains for the diagnosis of Helicobacter pylori. Gastric biopsy specimens obtained from January 2001 to December 2005 were reviewed. They were all stained with hematoxylin and eosin, GM and MB stains. The slides were examined on a blinded basis. Direct comparisons were made between the both stains. Two hundred thirty-six cases were studied with a concordance rate of 98.3% (Kappa value = 0.951, p < 0.05), showing good agreement. MB stain can be substituted for GM stain, and is preferred because it is cost-effective, less time-consuming, less complicated to perform, accurate and widely available. Useful hints to reduce false negativity with MB stain are discussed.