[Histonet] Mixing Paraffin Brands

Manfre, Philip philip_manfre <@t> merck.com
Wed Jun 19 13:40:12 CDT 2013

	Apparently I only responded to you directly.  I am re-sending my response in case anyone else on the net is interested.



Personally, I would not mix them, as they have somewhat different properties, such as the melting point.   I think you are asking for trouble, or inconsistent results at least, when compared to your normal product.  If you have more than one processor and embedding center, set up one of each with the other paraffin and use it on low-priority tissue, if such exists.  At least the infiltration and embedding matrix will be the same. Just my opinion.  


Philip Manfre, B.A., HT (ASCP)
Associate Principal Scientist
Merck Research Laboratories
PO Box 4
West Point, PA 19486

215-993-0383 (fax)
philip_manfre <@t> merck.com

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Lucie Guernsey
Sent: Wednesday, June 19, 2013 2:01 PM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] Mixing Paraffin Brands


Does anyone know if there's a reason why one shouldn't mix different brands
of paraffin? We normally use Fisherbrand's Paraplast Plus (melting point 56
C). We inherited about 8 bags of McCormick Paraplast X-tra (melting point
52 C). Will the different melting points be a problem?

If we were to use the McCormick paraffin, the only place it may mix with
the Fisherbrand paraffin is in the blocks themselves (as we refill the
embedder). But I don't want to compromise the quality of our blocks just to
not waste the free paraffin.

Or, another option could be that we use the McCormick in the processor and
the Fisherbrand in the embedder. Could that cause issues in the blocks as
the tissue would be infiltrated with one brand and embedded in another?

Maybe I'm over-thinking this......

Many thanks!

Lucie Guernsey
Dept. of Pathology
lguernsey <@t> ucsd.edu
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