Which stain combination is used to detect intestinal metaplasia?

• A. Alcian blue PAS hematoxylin
• B. Hematoxylin and eosin
• C. PAS only
• D. Masson's trichrome

Answer: (A)

Detecting intestinal metaplasia relies on staining that reveals the mucin types produced by goblet cells. In this condition, the gastric mucosa is replaced by cells that mimic intestinal mucosa and secrete intestinal-type mucins. Alcian blue stains acidic mucins blue, while the periodic acid–Schiff reaction stains neutral mucins magenta. Using them together (with hematoxylin as a nuclear counterstain) highlights goblet cells that contain both acidic and neutral mucins, making intestinal metaplasia readily identifiable. The other stains either do not differentiate mucin types (H&E), stain mainly connective tissue (Masson's trichrome), or stain mucins without the specific acidic/neutral distinction (PAS alone). Therefore, Alcian blue–PAS with hematoxylin is the stain combination used to detect intestinal metaplasia.