[Histonet] counter stain for PAS for fungus

[Steve McClain]

Change all your reagents.
Change periodic acid every week at least.

Personally I see little advantage in fast green, and a common downside is
overstaining in many labs, hiding fungus and basement membrane.
Faint Hematoxylin is acceptable counterstain.

For certain applications, e.g., dual staining for carbohydrate and mucin, adding AlcianBlue for 40 seconds is wickedly good.
Dis/Advantage being dual staining methods impose two charges.
Too bad.
Instead of separate stains for mucin and carbohydrate,
do them both every day and get good at it.
We rarely do a straight PAS any more.
Subtract the second charge where needed.

The two analytes (carbohydrate and mucin) are different, yet the interpretation is synergistic.
Where you see mucin glommed around a hypha-like structure it is.
It also demonstrates internal structure in many fungi.

AlcianBlue also stains bacteria, making it useful where polymicrobial (fungal and bacterial) infections are common.
Call it your biofilm assay.


So many fungi produce mucin that PAS-AB with hema is a superb method for detection.
PAS-AB sine hema is considerably more sensitive, especially with pigmented fungal species
but interpretation of PAS-AB without Hema is difficult for many pathologists.

Steedman wrote the paper in 1951.
Steve
Steve A. McClain, MD
McClain Labs, LLC 45 Manor Road, Smithtown, NY 11787 631 361 4000