I don't know about everyone else, and their labs, and the type patients they see, but I think it gives a false sense of security to only deconaminate a cryostat after a known infectious case.
At our inner city hospital, so many patients have HIV, hepatitis, and may have been exposed to TB, that we assume (That "ass" word again!) that the crostat is always contaminated (a form of universal precautions). While we are on the subject, how many people use a cryorefrigerant to speed up frozen sectioning, and in the process blow possible biohazardous agents around their cryostat cabinet? Do your pathologists have their head in the cabinet while spraying the specimen?!!

Mike Titford
USA Pathology
Mobile AL USA