By: Melinda Chow, M.S. HT (ASCP)
Frozen sectioning is a technique generally performed in a histopathological laboratory to obtain a rapid microscopic diagnosis. The freshly excised specimen arrives in the laboratory, is processed, sectioned in a cryostat and stained in less than 30 minutes. This technique is predominately used in the frozen room, next to the surgical unit of major medical centers to diagnose and confirm metastatic cancers. It is widely used in Mohs Micrographic Surgery laboratories for the removal of skin cancers and in major diagnostic laboratories that perform immunohistochemical, immunofluorescent and in situ hybridization tests. Recently, there are many research facilities employ this technique for enzyme detection studies, laser microdissection and transmission electron microscopic studies.
The preferred way of frozen sectioning is the brush technique that I advocate for in my workshop, Frozen Sectioning, which I presented at the 2018 NSH Symposium/Convention and as a webinar for the 2017 Laboratory Webinar Series.
When you start out learning frozen sectioning, learn the brush technique of frozen sectioning first. As Dr. Stephen Peters said, why put the young toddlers on crutches first before they learn how to walk?
Do not rely on the anti-rolling plate. Many times, the anti-rolling plate needs adjustment. Sections stick to the anti-rolling plate. The majority of the anti-rolling plates in the older model cryostats do not work well. It gets frustrating when you are trying to get good sections cutting on these cryostats.
Sometimes, I will get a call to come in to work at a particular office, and I walk into the Mohs Lab and notice the anti-rolling plate was taken off the cryostat. The regular Mohs technicians do not use it, so if you are proficient in using the brush technique, you will be fine without the anti-rolling plate. The brush technique is the better way to achieve wrinkle free quality frozen sections.
Below is an image of a 45 degrees angle cut brush that I use:
Your left hand with the brush will catch and guide the section and your right hand will turn the wheel of the cryostat in one continuous motion.