[Histonet] Paraffin vs. Cryostat

[Lee & Peggy Wenk]

Frozen sections (cryostat) are for when:
- there is a need for speed
- when fixing and processing tissue through to paraffin would 
destroy/extract the component needed for diagnosis

Speed - such as when the patient is still on the operating table and a 
diagnosis is needed immediately
Fixation/Processing destroy/extract - such as demonstration of lipids, 
muscle enzymes, some antigens

Paraffin embedded tissue also allows for thinner sections (e.g. 2 um 
kidneys), cutting of harder tissues (e.g., decalcified bone), and easier to 
store and retrieve archival blocks (store paraffin blocks at room temp for 
decades vs. needing a huge freezer for frozen tissue and hope for no freezer 
burn (freeze-dried) tissue in a couple of years). Well fixed processed 
tissue is no longer infectious (ignoring prions), while frozen tissue is 
still biohazardous.

So most people work with fixed processed tissues most of the time, and use 
frozen sections only when needed (time, extraction reasons above).

Peggy A. Wenk, HTL(ASCP)SLS
Beaumont Hospital
Royal Oak, MI 48073

--------------------------------------------------
From: "Hehl  Joachim" <joachim.hehl <@t> lmc.biol.ethz.ch>
Sent: Friday, March 11, 2011 5:48 AM
To: <histonet <@t> lists.utsouthwestern.edu>
Subject: [Histonet] Paraffin vs. Cryostat

> Dear all,
> I have a very basic (maybe stupid) question regarding the problem when
> should one use paraffin sections or better cryo sections. Since I have 
> heard
> so different opinions I would be glad to receive some founded
> recommendations and/or literature references comparing these two 
> techniques.
> Thanks for your help!
> Joachim
>
>
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