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Sweat and Puchtler’s Sirius Red for Amyloid

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%100mL
    Sodium hydroxide, 1% aqueous1mL
  • Sirius red
    Sirius red1g
    Distilled water100mL
    Sodium chloride0.5g

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

  • Amyloid  –  red
  • Nuclei  –  blue
  • Background  –  colorless


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

Safety Note

Prior to handling any chemical, consult the Safety Data Sheet (SDS) for proper handling and safety precautions.


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