Thioflavine S
for Amyloid Fluorescence

Mayer's Alum hematoxylin
Thioflavine S, 1% aqueous
Ethanol, 70%

Tissue sample
5-10µ paraffin sections of neutral buffered formalin fixed tissue are suitable.


  1. Bring sections to water via xylene and ethanol.
  2. Place into alum hematoxylin for 5 minutes.
  3. Wash with running tap water for 5 minutes.
  4. Rinse well with distilled water.
  5. Place into thioflavine S solution for 5 minutes.
  6. Rinse with distilled water.
  7. Place into 70% ethanol for 5 minutes.
  8. Rinse with distilled water.
  9. Mount in a fluorescence free aqueous mounting medium.

Expected results
With appropriate filters, amyloid fluoresces bright yellow. (UG1 or UG2 exciter filter and a UV barrier filter or similar).


  1. The pretreatment with alum hematoxylin suppresses nuclear fluorescence.
  2. Although the method specifies an aqueous mounting medium, either blotting and treating with xylene repeatedly until clear, or dehydrating with ethanol and clearing with xylene, then mounting with a fluorescence free resinous medium may be satisfactory.


The Internet Pathology Laboratory for Medical Education
Mercer University School of Medicine.,
Thioflavine S for amyloid




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