[Histonet] Decontamination of a Cryostat

Fri Jan 29 10:34:29 CST 2010

Hi Sharon,

I copied and pasted a chemical disinfection procedure for cryostats that I
created for Leica's sales and service employees and customers.  It
references Leica cryostats but it can be used for any cryostat--the basic
principles for chemical disinfection are the same.  Since we can't put
attachments on the histonet, I am hoping that you will be able to read the
copy without problem.  If any of you have trouble, please let me know and I
can send it to you off line as an attachment.

                     Chemical Disinfection of a Cryostat

  According to CAP regulations, a cryostat should be defrosted and
  decontaminated with a tuberculocidal disinfectant at a time interval
  appropriate for the institution (once a week for instruments used daily).
  The regulations also state that the cryostat must be clearly marked as
  contaminated if a frozen section is performed on tissue from a patient
  known or suspected to be positive for HIV, hepatitis B or C, SARS-related
  coronavirus, prion disease such as Creutzfeldt-Jakob disease, or
  mycobacterial or systemic fungal disease.  It must then be decontaminated
  before further use.

  ·   Wear Personal Protective Equipment (PPE):
   Personal Protective Equipment, such as gowns, puncture and penetration
  resistant gloves and eye protection must be worn when performing cryostat
  disinfection procedures.

  ·   Cryostat Preparation
  Remove used blades/knives from their holder. Although not a requirement,
  steel mesh gloves should be worn when changing knife blades. Dispose of
  blades according to the regulations of the institution or disinfect
  knives before reusing by soaking in disinfecting solution. Remove all
  debris and utensils (pencils, forceps, brushes, gauze, etc) from the
  chamber.  Debris must be removed because organic material (blood and
  proteins) may contain high concentrations of microorganisms and could
  possibly inactivate the chemical disinfectant or prevent access to
  contaminated surfaces.  It should be treated as biohazardous waste and
  disposed of according to the policies and procedures of the institution.

  70% ethyl or reagent alcohol can be used to clean the cryostat and
  provide some disinfection capabilities.  The germicidal activity of ethyl
  alcohol is most effective in the 70% range because it can penetrate
  tubercle bacteria and it has an advantage over isopropyl alcohol of being
  able to kill hydrophilic viruses.

  ·   Chemical Disinfection
  In order to disinfect a cryostat using a chemical disinfectant, the
  instrument MUST be at room temperature before the process is started.
  Turn off and unplug the instrument before beginning the disinfection
  process.  (Once the cryostat has reached room temperature, do not turn
  the handwheel until it has been returned to cold temperature.)

  Chemical Disinfection of a Cryostat continued:

  Do not create aerosols by spraying disinfectant (or anything else) in an
  open cryostat chamber.  Pour disinfectants onto surfaces or absorbent
  disposable towels and allow them to remain in contact with contaminated
  surfaces for the length of time specified in the instructions of the
  individual agents.  Use a tuberculocidal disinfectant that is
  non-corrosive. The EPA maintains a list of Antimicrobial Chemical/
  Registration Number Indexes on their website,
  http://www.epa.gov/oppad001/chemregindex.htm), and it is updated
  regularly. From this link you can find agents effective against
  bloodborne pathogens such as Mycobacterium tuberculosis, human HIV-1
  virus, and Hepatitis B or Hepatitis C virus.  It is critical to remember
  that NONE of these solutions have been tested at low temperatures and can
  only be used at room temperature.

  Any disposable material used in the disinfection process must be disposed
  of in accordance with the policies and procedures of the institution.

  ·   Following Disinfection
  After the disinfection procedure is complete, the cryostat and all of the
  accessories must be thoroughly dried and lubricated before being put back
  into service at cold temperatures.  Absolute ethyl alcohol can be used to
  remove excess moisture from surfaces.  Accessories with multiple parts,
  such as the disposable blade holder, knife holder and their respective
  bases, must be taken apart and dried thoroughly.

  Plug the instrument back in and turn it on.  Use only the lubricants that
  are recommended by the manufacturer and only in the recommended amounts.
  Lightly lubricate any moving parts.  To lubricate the specimen arm,
  extend it all the way forward.  Apply ONE DROP of lubricant to the barrel
  and spread it around with your gloved finger.  Move the arm back to the
  home position.

  The liquid waste container should be emptied in accordance with the
  policies and procedures of the institution.  Before replacing in the
  instrument, add a small amount of liquid bleach to the empty container.

  For optimum sectioning, allow the instrument to cool long enough to allow
  the metal microtome parts to reach the cold temperature setting.  The
  CM1850 requires no less than 3 hours and the CM1950 needs 5 hours to cool
  down from ambient temperature (20°C) to -25°C and 8 hours to cool from
  20°C to -35°C.

  Kind regards,

  Jan Minshew
  Marketing Manager
  Leica Microsystems
  Biosystems Division
  2345 Waukegan Road
  Bannockburn, IL 60015

  Office:  847.405.7051
  Cell:     847.970.8468
  Fax:     847.405.6560

  www.leica-microsystems.com

  Click Here for this month's special offers!
  http://www.leica-microsystems.com/bsdspecial

             "Sharon.Davis-Dev                                             
             ine"                                                          
             <Sharon.Davis-Dev                                          To 
             ine <@t> carle.com>            <histonet <@t> lists.utsouthwestern.edu> 
             Sent by:                                                   cc 
             histonet-bounces@                                             
             lists.utsouthwest                                     Subject 
             ern.edu                   [Histonet] Decontamination of a     
                                       Cryostat                            

             01/29/2010 10:16                                              
             AM                                                            

This issue seems to be rearing its ugly head in our lab once again.
What is the correct procedure for decontaminating a cryostat after let's
say a specimen from an HIV patient for a frozen was cut on it?  We have
a couple of different cryostats, one of them defrosts quickly and the
other one ices over and defrosts very slowly.  Our PA's assist with 98%
of the frozens and will use either one of the cryostats.  Our
pathologists, who perform frozens by themselves on a rare occasion,
prefer the cryostat that defrosts very slowly.  Of course the cryostat
that was contaminated was down awaiting decontamination when a
pathologist had to perform a frozen.  We are now being told that we need
to replace the cryostat that the pathologist doesn't like to use. So
have any of you had any issues like this and if you have how did you
handle it?  Are there any decontamination procedures available for a
quick turnaround?  Any help or suggestions will be greatly appreciated.
Thanks.

Sharon Davis-Devine, CT (ASCP)

Cytology-Histology  Supervisor

Carle Foundation Hospital

Laboratory and Pathology Services

611 West Park Street

Urbana, Illinois 61801

217-383-3572

sharon.davis-devine <@t> carle.com

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