[Histonet] Changing to reagent alcohol

[Bob Richmond]

Carole L Johnson, HT(ASCP)cm, QIHC(ASCP)cm at UCH/Memorial Central Hospital
in Colorado Springs asks:

>>We have been using ethanol in our lab and would like to change to using
reagent alcohol for the obvious reasons of cost and regulatory headaches. I
have been tasked with creating a validation/verification process. Does
anyone have any suggestions? Or better yet, information proving that we can
make the change without going through an extensive project?<<

What's commonly called reagent alcohol in histology is 90% ethanol, 5%
methanol, and 5% isopropanol. BATF calls this "SD3 modified" (regulation
SD3 is denatured only with methanol). You sometimes see a different
denaturant, methyl isobutyl ketone (MIBK), but it smells so bad most labs
don't use it.

Alcohol denatured with acetone is also available, and is NOT suitable for
histologic use (it removes the eosin in the dehydration sequence).

The proposal is to replace absolute ethanol, in order to avoid the nuisance
of complying with BATF regulations on potentially drinkable alcohol.

I've never seen a practical problem with this changeover. I have no idea
what the regulatory issues might be.

Bob Richmond
Samurai Pathologist
Maryville TN