Sweat and Puchtler's
Sirius Red for Amyloid

Mayer's hemalum
Neutral buffered formalin (pH 7.0)
0.1M borate or borate-phosphate buffer pH 9.0

Alkaline alcohol
Ethanol, 80% 100 mL
Sodium hydroxide, 1% aqueous 1 mL
Sirius red
Sirius red 1 g
Distilled water 100 mL
Sodium chloride 0.5 g

Tissue sample
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable.


  1. Bring sections to water via xylene and ethanol.
  2. Place into neutral buffered formalin overnight.
  3. Wash in tap water for 15 minutes.
  4. Place into alkaline alcohol for 20 - 60 minutes.
  5. Rinse well with distilled water.
  6. Place into sirius red at 60°C for 60 - 90 minutes.
  7. Rinse with buffer.
  8. Wash with tap water for 5 minutes.
  9. Stain nuclei with hemalum and blue.
  10. Dehydrate with absolute ethanol.
  11. Clear with xylene and mount with a resinous medium.

Expected results


  1. This method uses sirius red F3B. The dye sirius red 4B is not suitable.
  2. Sirius scarlet GG, CI 40270, may also be used.
  3. Amyloid displays deep green birefringence when viewed with crossed polarisers, one above and one below the section.


Sweat, F. and Puchtler, H., (1965),
Demonstration of amyloid with direct dyes,
Archives of Pathology, v 80, page 613




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