[Histonet] Re: Eosin to dye small Biopsies

[Robert Richmond]

Allison Scott at LBJ Hospital in Houston, Texas asks about the use of
eosin to dye small biopsy specimens.

Several replies mention addition of eosin to one of the processing
alcohols. I have never seen this done, in maybe 60 pathology services
I've worked in. (I'd know, because I nearly always examine the
paraffin block when I order recuts or send a case out for
consultation.)

It's a fine time-waster for the pathologist to mark small specimens
with dye while grossing. I've used Mercurochrome (merbromin, related
to eosin but with 26% mercury) which fortunately was banned in the USA
about ten years ago. I've used eosin, and I've used safranin (from the
microbiology lab's Gram stain setup). I don't know whether safranin
interferes with FISH, as eosin is well known to, nor do I know if you
can put safranin in the processing alcohol. And I've used Davidson
tissue marking inks.

I've never seen or heard of cobalt blue used for this purpose - is
this the insoluble coloring material, chemically cobalt aluminate?

Bob Richmond
Samurai Pathologist
Knoxville TN