Which stain is used as a general stain for tissue morphology?

• A. Hematoxylin & Eosin
• B. Immunohistochemistry
• C. Papanicolaou
• D. Oil Red O

Answer: (A)

Hematoxylin and Eosin is the general stain used to reveal tissue morphology. Hematoxylin binds acidic structures like DNA and RNA, coloring nuclei blue/purple, while eosin stains basic components like cytoplasm and connective tissue pink. This combination provides clear contrast to visualize overall tissue architecture, cell outlines, and morphological details important for routine evaluation. Immunohistochemistry is a targeted technique to detect specific proteins, not a broad morphology stain. Papanicolaou is a cytology stain used for exfoliated cells (e.g., Pap tests), not standard tissue sections. Oil Red O stains lipids and is used mainly on frozen sections to identify fat, not general tissue morphology.