Picro-Fuchsin Variants

The methods in the charts below are variations on the theme of picric acid to stain cytoplasm and muscle, and acid fuchsin to stain collagen. This simple formula has been modified for both dyes, so they have become characterised as incorporating a small molecular weight yellow dye in conjunction with a larger molecular weight red or blue dye at a distinctly acid pH. They differ from trichromes proper in that they never contain a polyacid, pH adjustment being done by the picric acid or some other acid. In spite of this, many histotechnologists consider these methods to be the simplest of the one step trichrome methods, since the basis on which they work is very similar.

Most of these variants can be used in a van Gieson type method, although the staining time may need to be changed, sometimes significantly. It may also be desirable to change the nuclear stain colour to enhance contrast with the collagen, i.e. if a blue dye is used for collagen then a red nuclear stain may be appropriate.




Dyes To conserve space, dyes and chemicals are identified by abbreviations. These are explained at the end of this page. With most browsers an explanation will appear if the cursor hovers over each abbreviation.
Amounts Fluids are given in mL, and solids are given in grams. Sat. means a saturated aqueous solution.
Picric acid Since dry picric acid can be explosive it is suggested that it not be dried and weighed, but that an appropriate volume of the saturated aqueous solution be diluted with water to obtain the concentration required. At room temperature, 78 millilitres of a saturated aqueous solution of picric acid contains 1 gram of the solid.
Acid fuchsin For small amounts of acid fuchsin an appropriate volume of 1% acid fuchsin in distilled water may be added to the picric acid solution. One millilitre of such a solution contains 10 milligrams of the dye.



Variant DW PA AF Other Comments
Fite 100 0.5 0.1   Sat. PA 40, DW 50, 1% AF 10
van Gieson 100 Sat. 0.05    
Hansen 98 Sat. 0.1 AC 0.3  
Lillie 100 1 0.1 HCl 0.25  
Ohlmacher 50 Sat. 50 0.5   Dilute sat. PA with DW
Schaffer 100 Sat. 0.15 AC 0.05  
Thompson 100 Sat. 0.13    
Unna 90 Sat. 0.25 Gly 10
NA 0.5
Weigert 100 Sat. 0.1    
Wilhelmini 90 AP 0.8 0.2 Eth 95% 10 AP explodes more easily than PA. Sat. = 1%.



Variant DW PA Dye Other Comments
Curtis 100 1 PS 0.1 AC 0.04
Gnanamuthu   Sat. 50 CR 2 AM 50 Dissolve the CR in the PA. Add AM. Boil until there is no smell of AM. Cool. Add minimal DW to dissolve any precipitate.
Herovici 50 Sat. 50 AF 0.05
MB 0.025
LC 0.05
Gly 10
Dissolve AF in PA. Dissolve MB in DW. Combine. Add Gly and LC.
Puchtler 100 Sat. SR 0.1    



Abb Meaning Abb Meaning Abb Meaning
Acetic acid
Acid fuchsin
Ammonium picrate
Congo red
Distilled water
Hydrochloric acid
Lithium carbonate
Methyl blue
Nitric acid
Picric acid
Ponceau S
Sirius red F3B


Gray, Peter. (1954)
The Microtomist's Formulary and Guide.
Originally published by:– The Blakiston Co.
Republished by:– Robert E. Krieger Publishing Co.

Kiernan. J.A., (1999)
Histological and histochemical methods: Theory and practice, Ed. 3
Butterworth Heinemann, Oxford, UK.




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