RE: CJD cases

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From:"Johnson, Mickey" <>
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Hi Donna,
I was the person who asked about this initially a couple of months ago
because we had a case and did frozen sections. Decontaminating a modern
cryostat with harsh chemicals is really impossible. During and after the
frozen sections, we handled the specimens on double layers of plastic backed
absorbent pads and used double gloves and face shield. This was done at the
regular grossing bench.  We cut blocks of tissue into plastic cassettes and
treated with concentrated formic acid (approx. 88%) for two hours.  This
grossing was done after about 7 days in 10% NBF. It took that long to order
and get the formic acid in. It must ship by ground transportation only.  I
do not believe that two hours in formic acid would be adequate for large
specimens because of the lack of penetration in that length of time.  After
the formic acid, the cassettes are returned to 10% NBF for 2 more days.
Although literature says the prion is inactivated by this treatment, they
also said that laboratories may want to process these specimens separately.
We took this approach and hand processed the tissues and saved all the
fluids and used paraffin for incineration along with all the solid waste.
We used an old microtome to cut the blocks and collected all the shavings
for disposal by incineration.  We decontaminated the microtome with FULL
STRENGTH bleach and 1N NaOH. Various sources recommend either 1N or 2N NaOH.
I do not recall a reference which mentioned 6N? 10% bleach is not adequate.
Most labs do not have to do this all the time, so I think it is better to
err on the side of caution.  
We are currently rewriting the hospital policy on handling CJD cases and are
including a statement that NO frozen sections will be performed and in the
future tissue from cases of suspected CJD will be sent to a reference lab
which handles these cases.  We have also refined the criteria and
responsibility for designating as case as Suspected CJD.  The one which
prompted my inquiry was really probably alcoholic dementia rather that CJD.

I hope this all helps a little.  The incidence of this disease is rare,
about 1 per million in the general and laboratory population, but the
outcome is death, so deserves some extra care.  Surgery personnel have a
much tougher time with their potential exposure and clean up.

I would like to take this opportunity to thank everyone on the histo-net who
responded to my inquiry. The general consensus was to not do frozen
sections.  That is the approach we are taking in the future. The references
for the CAP and CDC were very useful too. 

Thanks again.


Michael L Johnson, BS, HTL(ASCP)
Histology Supervisor
Department of Pathology
Sacred Heart Medical Center
W. 101 8th Avenue
Spokane, WA 99220

-----Original Message-----
From: []
Sent: Wednesday, April 19, 2000 10:49 AM
Subject: CJD cases

Hi All, 
     We had some questions arise this morning in our histology lab in 
relation to a possible  CJD case. First of all, does 96-100% formic acid 
render the virus inactive and is it ok to run a possible CJD case after it's

been treated with formic acid with other surgical biopsies on the same 
processor without the risk of contamination to the solutions and the other 
tissues? Also, as far as decontamination goes, is a 10% bleach solution 
enough? In speaking with our OESO department this afternoon, they mentioned 
an article published by the CDC  in May of 1999 that stated a either a 6N 
NaOh or a 2N NaOh should be used for treatment of tissue prior to processing

and using the 2N NaOh as the decontaminating solution. Also, one more 
question regarding where the tissue should be treated. Is it ok to treat the

tissue in a histology lab under a hood or should it be done in a "gross
room or autopsy suite? Thanks in advance for the information........ 
   Donna B. 

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