Congo Red Stain Kit

 

Intended use:

Congo red stain is intended for staining amyloid in tissue.

 

Principle:

Amyloid substance has a selective affinity to Congo red and can be stained readily. Congo red, which is an azo dye with linear configuration, binds hydroxyl of amyloid substance with its amino group while clings on fiber of amyloid substance in parallel and appears red.

 

Methods:

1. Deparaffinize according to a typical procedure and hydrate tissue in water.

2. Stain in Congo red solution for 10-20 minutes.

3. Differentiate directly in alkaline alcohol solution for several seconds.

4. Rinse in distilled water for 5 minutes.

5. Stain nuclei in Mayer's Hematoxylin for 2 minutes. Rinse in distilled water for 5 minutes.

6. Dehydrate and clear in the typical manner. Mount with mounting media.

 

Specifications:

 

Contents	3vialsx20ml/kit	3Btlsx100ml/kit	Components
Congo red solution	20ml	100ml	Congo red, Methanol
Alkaline alcohol solution	20ml	100ml	Potassium hydroxide
Mayer hematoxylin solution	20ml	100ml	Hematoxylin

 

Precaution:

• Both amyloid substance and elastin fiber will be stained by the Congo red but appear in different shapes, so distinguish the two carefully.
• Differentiate appropriately in alkaline alcohol solution. If not enough, collagen fiber will also stain; if excessive, amyloid will discolor.
• The unstained amyloid paraffin tissue will gradually lose the affinity to Congo red after one year of storage.

 

Expected Results:

Amyloid, erythrocyte, elastin fibre	——	Red
Nuclei	——	Blue
Background	——	Yellowy pink