Congo Red Stain Set, Bennhold, Amyloid

Newcomer Supply Beaker

Solution A: Congo Red Stain 1%, Aqueous   500 ml
Solution B: Alkaline Alcohol   500 ml

Product Options:

Part # 1038A 500 ml set $85.40 H


Part 1038A
Solution A: Congo Red Stain 1%, Aqueous 500 ml
Solution B: Alkaline Alcohol 500 ml


Additionally Needed:

Amyloid Animal Control Slides Part 4031
Xylene, ACS Part 1445
Alcohol, Ethyl Denatured, 100% Part 10841
Alcohol, Ethyl Denatured, 95% Part 10842
Hematoxylin Stain, Mayer Modified Part 1202
Coplin Jar, Plastic Part 5184 (for microwave modification)


For storage requirements and expiration date refer to individual bottle labels.



Newcomer Supply Congo Red Stain Set, Bennhold, Amyloid, with included microwave modification, is used for identifying extraneous protein deposits in amyloidosis, as well as minute amounts of amyloid. The use of polarizing lenses is an essential technique for visualizing amyloid positive areas and/or to confirm negativity.



Fixation: Formalin 10%, Phosphate Buffered (Part 1090)
Technique:  Paraffin sections cut at 8-10 microns
Solutions:  All solutions are manufactured by Newcomer Supply, Inc.

All Newcomer Supply Stain Sets are designed to be used with Coplin jars filled to 40 ml following the provided staining procedure. Some solutions in the set may contain extra volumes.



  1. If necessary, heat dry tissue sections/slides in oven.
  2. Deparaffinize sections thoroughly in three changes of xylene, 3 minutes each.  Hydrate through two changes each of 100% and 95% ethyl alcohols, 10 dips each.  Wash well with distilled water.
    1. See Procedure Notes #1 and #2.
  3. Place slides in Solution A: Congo Red Stain 1%, Aqueous for 1 hour.

        Microwave Modification: See Procedure Note #3.

  1. Place slides in a plastic Coplin jar containing Solution A: Congo Red Stain 1%, Aqueous and microwave at 70°C for 3 minutes.
  1. Rinse in two to three changes of tap water; rinse in distilled water.
  2. Differentiate in Solution B: Alkaline Alcohol, 5 to 30 seconds, agitating constantly until slide background is cleared of Solution A: Congo Red Stain 1%, Aqueous.
  3. Rinse in two to three changes of tap water; rinse in distilled water.
  4. Counterstain with Hematoxylin Stain, Mayer Modified (Part 1202), 3-5 minutes, depending on preference of nuclear stain intensity.
  5. Wash in running tap water for 5 to 10 minutes.
  6. Dehydrate in two changes each of 95% and 100% ethyl alcohol. Clear in three changes of xylene, 10 dips each; coverslip with compatible mounting medium.



Light Field Microscopy:                      

Amyloid Pink to red
Nuclei Blue

Polarized Light:                                      

Amyloid fluorescence Apple green



  1. Drain slides after each step to prevent solution carry over.
  2. Do not allow sections to dry out at any point during procedure.
  3. The suggested microwave procedure has been tested at Newcomer Supply. This procedure is a guideline and techniques should be developed for use in your laboratory.
  4. For optimal results sections should be cut at 8-10 microns. This will provide more intense staining and allow smaller amyloid deposits to be identified.  Sections cut too thin may show faint staining and sections cut thicker than 8-10 microns may display yellow birefringence.
  5. If using a xylene substitute, closely follow the manufacturer’s recommendations for deparaffinization and clearing steps.



  1. Luna, Lee G. Histopathologic Methods and Color Atlas of Special Stains and Tissue Artifacts. Gaitheresburg, MD: American Histolabs, 1992. 366-367.
  2. Sheehan, Dezna C., and Barbara B. Hrapchak. Theory and Practice of Histotechnology. 2nd ed. St. Louis: Mosby, 1980. 177-178.
  3. Modifications developed by Newcomer Supply Laboratory.