HPS, AFIP Modification
General Oversight stain

Also known as the Hematoxylin Phloxine Saffron stain, AFIP modification.


Saturated aqueous picric acid
Solution A
Phloxine B 1.5 g
Distilled water 100 mL
Solution B
Saffron 2 g
Absolute ethanol 100 mL

Tissue sample
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable as are many other fixatives.


  1. Bring sections to water with xylene and ethanol.
  2. Place in picric acid solution for 5 minutes.
  3. Wash with water to remove yellow.
  4. Stain nuclei with hemalum, differentiate and blue.
  5. Wash well with water.
  6. Place in solution A for 2 minutes.
  7. Wash with tap water for 5 minutes.
  8. Thoroughly dehydrate with absolute ethanol.
  9. Place into solution B for 5 minutes.
  10. Rinse well with absolute ethanol.
  11. Clear in xylene and mount with a synthetic resinous medium.

Expected results


  1. The saffron should be extracted by mixing with anhydrous ethanol in a tightly capped container, then placing in a 56°C oven for a few days. Store and use at room temperature. It has a limited life and is best when freshly made.
  2. Saffron is expensive. It may be available in East Indian grocery stores or health food stores as its most common use today is as a spice and food colouring.
  3. It is important that there be no water in the saffron solution and that sections be thoroughly dehydrated before it is applied.
  4. Usually, whole stigmata are more effective than ground saffron.
  5. Erythrosine B may be used instead of phloxine B.


Histological Staining Methods of the Armed Forces Institute of Pathology, 3rd ed. (1968)
Luna, Lee G.
McGraw-Hill, NY, USA




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