[Histonet] Re: Giemsa stain

[Marshall Terry Dr, Consultant Histopathologist]

Bob, always a great pleasure to read your wisdom.

Here though, you seem to be blowing hot then cold about a control for
Giemsa for Helicobacter.
Here's the crux - will you ever see a situation in which the tissue is
stained and the bacteria not?
I don't think so.

Terry 

PS
All stains work, Immuno is the most sensitive and easy to read, but not
of course to do.
The "blue" stains tend to be overdone.
Silver stains coat the organisms and make them look as if they are
wearing a woolly jumper!


-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Robert
Richmond
Sent: 14 November 2007 14:54
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] Re: Giemsa stain

The Giemsa stain is widely used as a stain for Helicobacter pylori in
gastric biopsy material. It's actually simpler to use a solution of
toluidine blue and related dyes in a neutral buffer (such as Diff-Quik
II and its many generic equivalents). There is adequate literature to
support this technique.

It's never good practice to stain for an organism without an appropriate
control slide, though in this particular case I don't really think it's
necessary from a technical viewpoint - the adjacent tissue provides an
adequate control.

In the USA, some regulatory agencies (this is a somewhat controversial
point) require mention of a control in the pathologist's report. My
usual microscopic note reads "a bacterial stain (generic equivalent of
Diff-Quik II, with a positive control slide) shows nothing to suggest
Helicobacter."

If the control slide doesn't contain any bacteria (frequently the case,
with histotechs who never look at a slide), I say "suitable"
rather than "positive".

The control should be a gastric biopsy specimen positive for
Helicobacter. The pathologist should inform the histotechs when a
suitable case to use as a control comes by. Of course, if you get a
gastrectomy specimen done for ulcer disease (shouldn't happen, but it
still does occasionally) then you're set for control sections for life.

Slides often need to be examined with an oil immersion lens. I do this
with all positive specimens, and with apparent negatives when chronic
active gastritis (neutrophils infiltrating between the gastric pits) is
present.

I don't think immunohistochemistry is more sensitive, but reading the
slides is an awful lot faster - important if you've got 10 gastric
biopsies on your desk. I have no experience with the silver techniques
occasionally used.

Bob Richmond
Samurai Pathologist
Knoxville TN

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