Thanks, Cliff Berger at www.decal-bone.com for reminding us that >>Decal is a 
registered trademark of Decal Chemical Corp.<< When I replied to this query 
before, I was on the road and without my reference books.

As many readers of this list know, I'm an elderly pathologist who does locum 
tenens work, and thus sees many different working hospital and private 
histopathology labs. 

Cliff's observation that >>the trouble with most decalcified tissue is not 
the type of decalcifier used but the specimen handling before and after 
decalcification. Proper fixation is usually the most important factor in good 
decalcified specimens<< is entirely correct. Let me add several practical 
points to that.

If a piece of bone isn't thin enough to fixed overnight, it needs to be cut 
down with a saw until it is thin enough. If a femoral head arrives over the 
weekend, it needs to be slabbed on Monday, the slab fixed overnight, and 
decalcification begun on Tuesday. If the pathologist objects to the delay, he 
can come in over the weekend and slab the bone, and, if he comes in twice, 
decalcify it also. (Dream on.)

Pathologists need saws, and what they want varies. Many pathology services 
supporting orthopedic services no longer have a saw at all! I am unwilling to 
use a Stryker oscillating saw (there's often one of these left over from an 
otherwise forgotten autopsy kit) on a piece of loose bone with no clamp. The 
old Satterlee amputation saw looks like something left over from the Civil 
War, but it's a good saw for those of us who aren't comfortable with 
hand-hazardous power tools. Still better is a double-bladed saw made for the 
purpose. Since the Satterlee saw is over $70 (from whatever Lipshaw is called 
this week) and the specially-manufactured double-bladed saw about $500, the 
pathologist can't have one in these days of Good Management, so I routinely 
go to a hardware store and buy a five dollar hacksaw. 

Who is responsible for completing the decalcification, the pathologist or the 
histotechnologist? This question needs to be settled for every specimen. A 
couple of weeks ago I was working in a lab I'd never worked in before. Got an 
important decalcification specimen - a curetted bone tumor - carefully fixed 
and and put it into (the real thing, Cliff) Decal. The histotechnologist - a 
pleasant elderly woman who had clearly never looked at a slide in her life, 
and wasn't about to start at the behest of a wandering pathologist - put the 
specimen away and never mentioned it to me again until I asked her about it 
at the end of the week. It appeared that I was supposed to go get it off the 
shelf and get it into a cassette. Bad slip-up, but the sort of thing one is 
apt to fall into the first week on the job

Cliff adds: >>Second, decalcifiers that contain HCl (hydrochloric acid) 
should never, and we mean never, be mixed directly with formalin. The 
combination of HCl and formaldehyde causes an extremely carcinogenic vapor 
known as bis-chloromethylether.<< Uh, Cliff, you left something out here - do 
Decal and Decal-Stat contain hydrochloric acid? - I've heard the 
bis-chloromethylether story and I've also heard it's an urban legend. John 
Kiernan, do you know the answer to this? I don't.

Histopathology laboratories are losing the skills needed to prepare and cut 
ordinary calcified tissue. To keep them up, it's important for pathologist 
and histotechnologist to insist on good preparation of ordinary junk bone 
specimens - femoral heads from fractures are an important specimen to focus 
on, since they're common, reasonably easy to prepare, and actually of some 
clinical importance, since unsuspected pathologic fractures (fractures 
through deposits of metastatic cancer in the bone) are reasonably common and 
are important to diagnose. 

A worthwhile reference likely to be on a pathologist's book shelf is in one 
of the AFIP fascicles: Tumors of the Bones and Joints, AFIP Atlas of Tumor 
Pathology Third series fascicle 8, by Robert E. Fechner and Stacey E. Mills 
(Charlottesville VA), AFIP/UAREP 1992.

Bob Richmond 
Samurai Pathologist
Knoxville TN