Re: cryostat decontamination

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From:Tim Morken <>
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First of all, there has been only one reported case I know of in which a 
person was infected by material from a cryostat, and that was blamed on 
using freezing spray on a TB sample. So the threat is probably minimal.

Second, the point of my original post was that there are several 
decontamination methods in use but none have published data to support their 
effectiveness. One method has unpublished data to support it (formalin vapor 
method). That method was tested on bacterial cultures in petri dishes placed 
in a defrosted cryostat. They achieved a full kill of the bacteria. Viral 
cultures were not tested. The method may not work as well on OCT embedded 
tissue shavings sitting in a cryostat.

I can't say if the methods in general use are doing a good job (because I 
don't want people to say I stated something in favor of any procedure) but 
Histotechs don't seem to be catching bugs from their cryostats so maybe the 
methods are adequate at the least.

Tim Morken, B.A., EMT(MSA), HTL(ASCP)
Infectious Disease Pathology
Centers for Disease Control
1600 Clifton Rd.
Atlanta, GA 30333


Phone: (404) 639-3964
FAX:  (404)639-3043

----Original Message Follows----
Subject: Re: cryostat decontamination
Date: Sun, 5 Mar 2000 09:49:59 EST

I have heard the formalin decontamination, plan before, but does this really
rid us of
contaminants, like afb (especially now with the multiple strain drug
the virus for Aids? Some literature suggests that the virus can be found in
dry smears years later? Shouldn't we be bleaching and using fomaldehyde in 2
steps of course. I don't want to freak out or cause a scare, but are we
really taking good care of ourselves and our technical staff? I am as
confused as the rest as to what is truly a good procedure.

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