[Histonet] Extended time in paraffin

valleygal <@t> aol.com valleygal <@t> aol.com
Fri Feb 23 10:42:28 CST 2007

Can you select the number of the station that you want to delay the 
tissues in until processing starts? If you can, you could have the 
tissues go through the formalins like usual and delay when they get to 
the first alcohol station. The processor should then start up and 
continue on with the processing in time for the tissues to be done 
early Mon AM.
Otherwise, either option 2 or 3 would work. 2 would take less time to 

Andi Grantham

-----Original Message-----
From: RohrT <@t> nyackhospital.org
To: Histonet <@t> lists.utsouthwestern.edu
Sent: Fri, 23 Feb 2007 9:14 AM
Subject: [Histonet] Extended time in paraffin

I have a problem with processing breast tissue over a weekend. Breast 
tissue is
run in a separate processor from our Sugical and endo specimens. We do 
not have
weekend staff. We usually run a two day delay with the processing 
Sunday night and both processors ending early Monday AM.

The current guidelines suggest this delay of breast tissue sitting in 
could result in over fixed breast tissue.  The pathologists want to end 
cycle on Saturday but we have no staff here to remove and/or embed the 
The pathologists themselves would have to remove the cassettes from the

The questions are what can they do with these cassettes? Again, the 
tissue is
breast tissue, mainly cores or target blocks or tumor that may need IHC 
FISH on diagnosis

1.  Can they just leave the cassettes on the processor in warm paraffin 
degrees) from Saturday until Monday?
2.  Can they remove them from the paraffin and let them harden at room
temperature and then be heated, melted and properly embedded on Monday?
3.  Can they put the cassettes in a container of warm paraffin "to 
cover" and
then let the whole container solidify and on Monday Histo melts the 
removes the cassettes and embeds?

 I have only found two clear commentaries.
  Sheehan and Hrapchak who say extended time in paraffin will cause 
shrinkage and
hardening. There is also a reference in Carson, saying tissue should 
remain in
paraffin the shortest time necessary for good infiltration as prolonged 
causes shrinkage and hardening.

Can any of you offer me any further references and/or assistance or 
your own

Thank you so much for your time and assistance
Theresa Rohr
Nyack Hospital, NY
rohrt <@t> nyackhospital.org

Theresa Rohr, BA, HT(ASCP)
Section Head, Histology
Nyack Hospital
160 North Midland Avenue
Nyack, New York 10960
phone 845-348-2276
fax 845-348-8430

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