Re: [Histonet] Frozen IF Specimen Storage: Is -80 C really necessary; will -20 C work?

margaret chadwell m_chadwell <@t>
Mon Nov 11 13:46:35 CST 2013

Hi David,

An institute that I work for would take the samples out of the -80 and place them into a -20 before I cut them, sometimes this would be overnight other times several hours. We were experiencing freeze thaw artifact on those samples, when asked why they were doing this, they thought this was the recommended protocol. Once they stopped the practice, and left the samples in the -80 till cutting, no freeze thaw artifact was encountered again. As a result of this, I would recommend you don’t place them in the -20. I also only remove the samples I want to cut at the moment and don't place many samples in the cryostat at one time.

Margie Chadwell

Sent from Windows Mail

From: Rene J Buesa
Sent: ‎Monday‎, ‎November‎ ‎11‎, ‎2013 ‎8‎:‎09‎ ‎AM
To: DAVID HENDERSON, histonet <@t>

I really do not know of any study comparing -20ºC vs -80ºC or if this -80ºC is the result of a commercially driven  "ideal" storage method. I advise you to check about any bibliographic references BUT meanwhile I also advise you to keep your precious and irreplaceable material at -80ºC. I do not think that you should risk losing all your samples just to work "on the cheap". 
I always kept my tumor bank and IF samples at -80ºC and when our freezer also died year ago, I was lucky enough to get the approval to buy a new one.
 Do not rush to save money
René J.

From: DAVID HENDERSON <dhenders01 <@t>>
To: "histonet <@t>" <histonet <@t>> 
Sent: Sunday, November 10, 2013 6:56 PM
Subject: [Histonet] Frozen IF Specimen Storage: Is -80 C really necessary; will -20 C work?

We routinely store our frozen IF specimens (renal and skin biopsies) embedded in OCT and sealed in plastic bags for at least 4 yrs in a -80C freezer. Cases that are positively diagnosed by the pathologist, are used as positive controls for subsequent IF staining. In practice, most positive controls are used within 1-2 years of their original storage.

Our -80C freezer has died, and we are temporarily storing in a different -80C freezer in another building on campus. My supervisor asked me to research whether or not a -20C freezer will suffice for our storage needs, or must we anti up for the much more costly -80C replacement or repair. 

I would appreciate receiving suggestions backed by experience, or educated thoughts about the advisability of -20C storage of specimens for future IF staining.

David Henderson, HTL
RML, Tulsa, OK

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