Periodic Acid-Schiff (PAS): Counterstaining with Hematoxylin

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Periodic Acid-Schiff (PAS): Counterstaining with Hematoxylin

Hematoxylin should be used as a counterstain when the PAS is employed to demonstrate glycogen and mucins. When using a hematoxylin counter-stain, continue any of the PAS staining protocols with the following steps:

Reagent

Time

Harris hematoxylin with acetic acid:

2 mL acetic acid with 48 mL hematoxylin

30 seconds

Running tap water

Rinse well

In addition to the PAS reaction, expected results:

  • Purplish-blue nuclei

Post staining procedure:

  • After counterstain, tissue sections should be rinsed well in distilled water, dehydrated with 95% alcohol, followed by 100% alcohols, cleared with xylene (or xylene substitute), and cover-slipped.

PAS with hematoxylin counterstain demonstrating basement membrane in kidney