Lesson Summary

This lesson introduces the development and clinical significance of the PAS stain.

Learning Objectives

• Understand the historical development of PAS staining.
• Explain why PAS is widely used in pathology.
• Identify major PAS-positive tissue components.

Content

The Periodic Acid-Schiff stain was introduced in the 1940s and quickly became an essential special stain in histopathology.

PAS staining is used to detect substances containing carbohydrates or carbohydrate-rich structures including:

• Glycogen
• Neutral mucopolysaccharides
• Basement membranes
• Fungal cell walls
• Glycoproteins

PAS is commonly used in:

• Renal pathology
• Liver pathology
• Hematopathology
• Microbiology
• Dermatopathology

Key Takeaway

PAS highlights carbohydrate-rich tissue components with a magenta coloration.