Lessons from the experimental stage of the two-step vacuum-microwave method for histoprocessing.

The two-step vacuum-microwave method simplifies and shortens histoprocessing. Acting margins are small so that fine-tuning is required. Temperature, vacuum and time should be in perfect balance. If not, a "cooking" effect (too high temperature) can easily be detected in the epidermis of skin biopsies. An adverse vacuum effect (when vacuum is obtained too abruptly) produces clefts, first observed where different tissues are contiguous. When time is set too shortly, impregnation will be insufficient, which is best seen in kidney tissue. The lessons from these observations may help future users to be troubleshooters while installing their unit.