Re: Paraffin temp for immuno's
|From:||Vinnie Della Speranza |
it is always dangerous to generalize especially because we use ihc to stain
for a wide variety of cellular and tissue antigens and something is always
likely to be the exception however I'm going to risk it.
The rule of thumb is to try to prevent overheating of tissues during
exposure to processing chemicals. There are certainly proponents of low metling
point paraffins but we have a very successful immunohistochemistry laboratory
that routinely utilizes a 58 degrees metling point paraffin. I do not recommend
that you change paraffin to resolve your quality issues as I personally don't
believe that this is likely to make the difference. Lastly I would add that in
my opinion, if your tissues are well fixed, most if not all antigens will
survive exposure to 60 degrees. Its interesting to note that we frequently
expose tissues to very high heat (90-100 degrees C) to achieve epitope retrieval
which seems to contradict this notion that temperatures must be kept as low as
Vinnie Della Speranza
Manager for Anatomic Pathology Services
University of South Carolina
165 Ashley Avenue Suite 309
>>> Ross Stapf
<firstname.lastname@example.org> 10/16/02 04:04PM >>>
I was reading through Diagnostic Immunohistochemistry by Dabbs
and came across a comment that paraffin temperatures should not exceed 56
degrees when doing immuno's on the tissue later.
We have been trying to
standardize our methods for optimal immuno results. We have the occasional
case where the staining is not as expected. We are trying to eliminate as
many of these problems as possible. Is the paraffin temp really that
important? I am beginning to wonder if this is one of the reasons for
those cases that should, but just don't stain positive.
been using Paraplast and Paraplast xtra for over 10 years at 60 degrees.
If I do experiment with a paraffin with a lower melting point, what can I
expect? Will my techs have a harder time cutting the blocks? Will I
need to increase my infiltration times?
Turn around time is very
important, I don't want techs complaining that they can't get good routine
sections just to possibly fix an immuno variable. Also from my research so
far the lower melting point paraffin is more expensive.
anybody made a change in paraffin for this reason, and was it worth
Takoma Park MD
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