Re: soaking blocks

From:Connie McManus <>


As mentioned in my post (included below), I only soak my blocks for
10-30 seconds... approx. the time to face a block.  I recently changed
my processing schedule and am finding that, with the exception of spleen
or bloody tissues, I don't need to soak my blocks any more.  My schedul
is as follows:

Formalin.... 15 min. (tissues are well fixed by this time)
70% ETOH.... 40 min.
95% ........ 40 min
100%, 3 changes... 40 min each
100% ETOH/ Histoclear 1:1 .... 40 min
Histoclear, 3 changes... 40 min each
parraffin, 3 changes .... 1 hr each.  

This schedule is shorter than the former schedule by 3.75 hours.  I
average about 20 blocks per day, ranging from 0 to 65 blocks. I have a
Leica TP1050 processor. I change solutions once per month and paraffin
clean once each week. Another advantage of this shorter processing time
is that the pathologists have until 9:45 PM to put tissues on the
processor.  Previously it was 6:00 PM.  This is a big savings for them,
especially when it's 4:30 PM and someone brings in a dead cow or horse
to be necropsied.

Hope this helps.

Connie McManus

Otis Lyght wrote:
> Hi All,
> Seems there is lots of discussion of "block soaking". I work in a lab that
> deals with animal tissue. We soak  liver blocks sometimes for up to 2 hours
> and tissues sometimes still appears to be dry when mounted on the slide=2E
> Would anyone who is soaking or not soaking share their tissue processing
> schedule. Our total processing time runs approx. 7 hours for mice and 8
> hours for rat (three hours of this is 3 paraffin changes with the remainder
> being dehydrating and clearing). Would love to get some feedback on this.
> Thanks.
> Otis Lyght
> At 08:10 AM 3/15/01 -0700, you wrote:
> >Renee,
> >
> >you soak your blocks for 10-15 MINUTES????  wow.  I work with vet stuff,
> >too and find that only the livers, spleens and sometimes kidneys (if
> >there is a lot of blood in them) are about the only tissues I soak.  And
> >I only soak for 10-30 SECONDS.  I try to minimize soaking, but for
> >bloody, friable tissues, it can't be helped.
> >
> >Connie M
> >
> >Renee Escalona wrote:
> > >
> > > I'll have to admit, soaking blocks over night on ice does seem a little
> > excessive.   I work in a veterinary lab so of course all we do is process
> > and cut animal tissue.  I would say that on average we let our blocks
> > soak and chill for about 10-15 minutes.
> > >
> > > Renee Escalona, BS, HTL(ASCP)
> > > Diagnostic Laboratory Supervisor
> > > Texas Veterinary Medical Diagnostic Lab
> > > College Station, TX
> >
> >--
> >ࡱ


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