Hughesdon's Metachromatic Stain


Staining solution
Azure A 0.2 g
Distilled water 100 mL
Differentiating solution
Uranyl nitrate 0.2 g
Distilled water 100 mL

Tissue sample
Paraffin sections of neutral buffered formalin fixed tissue are suitable. Mercuric chloride fixatives are reputed to emphasise metachromasia. Other fixatives may be satisfactory.


  1. Bring sections to water via xylene and ethanol.
  2. Do a Mallory bleach using 1% potassium permangate alone for 5 minutes.
  3. Place in to staining solution for 5 minutes.
  4. Rinse with tap water.
  5. Place into the differentiating solution for 10 seconds.
  6. Rinse with tap water.
  7. Blot dry, dehydrate with absolute ethanol.
  8. Clear with xylene and mount with a synthetic resinous medium.

Expected results
Acid mucopolysaccharides = Red/purple
Mast cells = Red/purple
Background = Blue


  1. The time of differentiation should be adjusted to give good colour contrast.
  2. Metachromatically stained materials include acid mucins, cartilage, connective tissue ground substance and mast cell granules.
  3. It may be difficult to obtain uranyl nitrate due to restrictions placed on its distribution in some jurisdictions.

Drury, R A, and Wallington, E A, (1967).
Carleton's histological technique., Ed. 5. pp. 2250
Oxford University Press, London, England.




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