[Histonet] Control Slides

Lee & Peggy Wenk lpwenk <@t> sbcglobal.net
Thu Mar 10 18:38:56 CST 2011

I've noticed that our spirochete control slides don't stain as intense 
starting about 3 months after they are sectioned, and that they stop 
staining by about 6 months. (This is with a silver stain.)

I've talked with other histotechs, and they say they've seen the same 
phenomenon with AFB and Gram controls. (We use ours up too quickly - we 
never have 6-12 months old control slides for these, so I can't attest to 
this. )

Bancroft's book talks about this phenomenon with amyloid, and suggests that 
oxidation of the tissue (proteins) due to exposure to air may be the cause. 
I'm guessing the it probably applies to the precut microorganism control 
slides, too.

We only cut enough slides for 6 months, and date them. Other people say they 
put their cut control slides in a slide box with a lid after drying, and 
then place the box in the refrig, as cold slows down the chemical change, 
and the lid keeps the moving air off the slide. Other people say that, after 
they dry the slide, they dip the slide in paraffin, to cover the tissue, so 
that the air doesn't touch the tissue during the months before the slide is 
used in a stain. Just 3 suggestions to stop this problem.

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

From: "Amador, Amanda" <aamador <@t> ameripath.com>
Sent: Wednesday, March 09, 2011 10:22 PM
To: <histonet <@t> lists.utsouthwestern.edu>
Subject: [Histonet] Control Slides

> Is there guidelines for how long special stains controls are good for once 
> they are cut?  We have spirochetes for our Steiner that is from 2007 and 
> we are having issues.
> Amanda Amador, HT(ASCP)CM
> AmeriPath | Histology Group Lead/Trainer |2560 N Shadeland Ave, Suite A | 
> Indianapolis, IN  46219 | phone 317.275.8052 | 
> aamador <@t> ameripath.com<mailto:aamador <@t> ameripath.com> | 
> www.AmeriPath.com<http://www.ameripath.com/>
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