Giemsa stain demonstrates which of the following features?

• A. Mast cells or H. pylori
• B. Nissl substance
• C. Amyloid
• D. Reticulin

Answer: (A)

Giemsa stain is a Romanowsky-type stain that highlights certain cellular components and microorganisms. It is well known for producing metachromatic staining of mast cell granules, so mast cells stand out with a distinct color. It also stains Helicobacter pylori in gastric mucosa as dark, well-defined rods against a lighter background. This makes the features described by the option correct. Other features are identified with different stains: Nissl substance is demonstrated with Nissl staining in neurons; amyloid with Congo red; reticulin fibers with silver-based reticulin stains.