[Histonet] Re: gout processing procedure

[Patrick Laurie]

Processing from 100% alcohol is important, but so is the cutting and
staining.  Don't cut sections and place onto a regular waterbath and expect
all of the crystals to survive.  Some still will, but we cut and place onto
a 100% alcohol bath.  I'll tell you though it can be difficult to get good
sections on an alcohol bath.  Then we stain them using an eosin only
protocol, skipping any aqueous steps (like hematoxylin, bluing, clarifier,
wash steps, etc).  The pathologist looks at them using polarizing filters
looking for birefringence. We tried doing the De Galantha silver method, but
it was too complicated.  Good luck!

On Tue, Aug 30, 2011 at 1:53 PM, Bob Richmond <rsrichmond <@t> gmail.com> wrote:

> Gouty tissue - containing monosodium urate crystals - should be fixed
> in absolute alcohol, and processed into xylene and paraffin directly -
> a rather cumbersome thing to do.
>
> Urate crystals, particularly in large deposits (tophi), often survive
> formalin fixation and routine processing anyway.
>
> If any crystalline material is seen on gross examination, it's better
> to pick it out with a needle, suspend it in a drop of water or
> alcohol, and look at with a polarizing system that includes a full
> wave plate (the pee lab microscope usually has one of these, the
> pathologist usuallly doesn't). If you see the characteristic
> negatively birefringent crystal needles with this approach, you don't
> need to do anything else.
>
> Bob Richmond
> Samurai Pathologist
> Knoxville TN
>
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-- 
Patrick Laurie HT(ASCP)QIHC
CellNetix Pathology & Laboratories
1124 Columbia Street, Suite 200
Seattle, WA 98104
plaurie <@t> cellnetix.com