[Histonet] Re: Amyloid Stain

[Robert Richmond]

I'd interpret a request for an amyloid stain as just that - rather
than immunohistochemistry.

Congo red is of course the traditional dye for staining amyloid. It's
long been out of use in the textile industry, and apparently is
manufactured in small quantities for histologic use, and is certified
by the Biological Stain Commission as an amyloid stain. I'm not
certain it's still in manufacture.

Holde Puchtler introduced Sirius red as a substitute for Congo red in
the 1970's, and it still has some vogue. Once again it may not be in
manufacture.

Dick Dapson at Anatech (www.anatechltdusa.com - I have no connection
with them) introduced "Amyloid Red" (Direct red 72, C.I. 29200) as an
amyloid stain. He describes it as rather similar to Congo red. I
haven't seen it - has anyone? You can get it from Anatech.

Examination of a dye stain for amyloid requires a polarization system
(and no, I don't mean a pair of broken sun glasses in the desk
drawer), and if the pathologist doesn't have access to a polarizer
(many of us don't) you probably ought to be sending out your amyloid
stains.

Finally, control material is hard to get. (The best controls I've seen
in recent years have been sections of medullary thyroid carcinomas.)
Supposedly undeparaffinized sections don't keep for more than a month,
so that the control block may need to be recut for each occasional
use, obviously an unthrifty procedure.

I've asked this question several times over the years and never got an
answer. It's fairly easy to produce amyloidosis in laboratory animals.
Why isn't animal material available for controls?

Bob Richmond
Samurai Pathologist
Knoxville TN