Special Stain - Azure A

This is one of the more reliable metachromatic techniques in that a reasonably alcohol fast metachromasia is imparted to a wide range of acidic mucins.? The alcohol-fast metachromasia is attributed to the use of a pre-oxidation step using potassium permanganate, and the bright staining effect to the use of Uranyl Nitrate as a differentiator.

Below is how to perform the Azure A technique

1. Take sections to water
2. Treat with potassium permanganate for 5 minutes
3. Wash in water.
4. Bleach in 5% oxalic acid solution for 30 seconds.
5. Wash in water.
6. Stain in azure A for 5 minutes.
7. Wash in water for 5 minutes.
8. Differentiate with 0.2% uranyl nitrate solution for 10 seconds
9. Wash in water then dehydrate, clear and mount

Acid Mucins	Purple to red in colour
Background	Blue

The results above are seen below.

Photo – x10 Azure A staining