RE: [Histonet] Re: HER2 and the 48 hour rule
I think CAP is addressing the issue of under fixed samples by saying that
your methods must be compared or validated against methods using a minimum
standard formalin fixation, if you do not fix long enough to protect the
sample from alcohol and xylene processing I don't think the samples are
going to stand up in this comparison with adequately formalin fixed samples
then paraffin processed which you have to demonstrate. Alcohol and glycol
fixatives are a problem for her2 as it really loves alcohol and you may get
more positives when compared with adequate formalin fixation which should be
used as the standard.
[mailto:firstname.lastname@example.org] On Behalf Of
Sent: Tuesday, January 23, 2007 5:23 PM
Subject: [Histonet] Re: HER2 and the 48 hour rule
Here's a truly radical solution: if the pathologist on call comes in on
Saturday (or Sunday) morning, let the pathologist embed the breast biopsies!
about time pathologists learned to embed.
Short of that revolutionary approach, I'd want the tissue to fix overnight,
then be passed to 70% alcohol, then processed Sunday night. - But it isn't
known that this approach works, and it doesn't comply with the rules (which
new, actually). But it's got to be preferable to leaving the specimen in
xylene (or substitute) or in molten wax.
Don't forget the issue of non-formalin fixatives, including glyoxal - they
haven't been tried.
I'm more concerned about tissue that isn't left in formalin for long enough.
If it's not, it fixes in the processor in alcohol. I'm even more concerned
about delay in fixation. In many radiology services, stereotactic and
wire-localization specimens aren't placed in formalin until after specimen
completed and the specimen is leisurely taken to the pathology lab.
I was appalled, but not surprised, by the CAP's failure to address any of
Let's remind ourselves what's at stake here. HER2 status determines whether
patient is treated with trastuzumab (Herceptin), a $50,000 treatment with a
potential for damaging the heart. Estrogen receptor determination is also
affected by fixation, and expensive and hazardous treatment depends on that
The lack of concern about this issue by primary care physicians, surgeons,
and oncologists once again underlines the "redhaired stepchild" status of
anatomic pathology in the laboratory and in the health care system. Remember
when you read the newspapers and magazines and read that faceless
are responsible for all of these procedures.
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