[Histonet] Re: Iron leaching out during decal

[RSRICHMOND <@t> aol.com]

Bethany J. Krafels describes difficulty in >>HTL Practical test and I am 
required to do a Prussian Blue iron stain on a 1.0 cm piece of bone.<<

I presume that you're allowed to use cancellous bone (the relatively soft 
bone of the interior of the vertebral bones, with red marrow) since that's what's 
normally stained for iron. This specimen needs to be obtained at autopsy, 
from a patient with presumably normal iron stores (the pathologist doing the 
autopsy should know this), slabbed out of a lumbar vertebral body with a hand saw, 
about 2 mm thick (this would take me a couple of minutes to do, and is 
something I'd probably do anyway). The slab should be fixed overnight (or a little 
longer) in neutral buffered formalin. Most of the standard decalcifying agents 
should decalcify it in the course of a working day, or overnight; check it, 
and don't leave it in the decalcifier any longer than needed. Take it from there 
like any other piece of tissue. If it doesn't work the first time, try it 
again with another case.

Zenker's fixative is the queen of battle for marrow morphology, but is not an 
ideal fixative for hemosiderin iron, because it's acid enough to leach some 
of it out. Neutral buffered formalin is exactly the fixative you need.

Bob Richmond
Samurai Pathologist
Knoxville TN