Frozen Section Technique & Cryostat

Introduction

Dr. Louis B Wilson described the procedure of the frozen section.

The frozen section technique is a procedure carried out in the histopathology lab to perform a rapid microscopic analysis of a specimen. It is also used to analyze tissue for cancer diagnosis. It’s a significant procedure used in Enzyme-Histochemistry, Immuno-Histochemistry, detection of lipids, etc. The technical name for this procedure is cryo-section. The instrument for cryo-section is the cryostat which is essentially a microtome inside a freezer. The microtome is capable of slicing tissue sections as thin as 1 um.

Specimen collection 

• The surgeon will take a biopsy of the tumor and send it to the histopathology lab.

• The histo-technologist quickly performs the frozen section technique by cryostat microtome.

• The histo-pathologist identifies the pathology and makes a diagnosis.

A Cryostat is a microtome machine used to cut tissue sections at low temperatures( typically around -15°C to -30°C).

Types of Cryostat:

1) Rotary Cryostat-(Single Compressor & Double Compressor)

2) Motorized Cryostat-(Single Compressor & Double Compressor)

Working Process

• First, switch ON the cryostat 10 to 15 minutes before use to maintain the temperature.

• Now, set the temperature according to the type of tissue by using the manual book of the cryostat.

• After maintaining the temperature start the process of the frozen section technique.

Care & Maintenance

1. Routinely, after the frozen section

• Always check the levels of the waste in the waste container before and after use. And discard if required.

• Wear protective clothing. A long-sleeved laboratory coat or gown with elasticized wrist bands, rubber gloves, and safety goggles afford the minimum standard of protection.

• Remove the microtomy debris from the cryostat chamber and place it into a fixative, disinfectant, or wet bag for autoclaving.

• Clean the knife and all exposed surfaces and instruments with 70% ethanol.

2. Monthly

• Wear protective clothing, same as routine maintenance. 

• Turn off the power switch and unplug the cryostat. 

• Rinse the cabinet and the microtome with 70% ethanol, then defrost overnight. 

• Then place a waste bucket containing 5% sodium hypochlorite below the drain outlet of the cryostat.

• Remove the microtome from the cabinet after defrosting and wash with hot water containing detergent, then rinse in absolute ethanol and allow to dry. 

• All sliding parts should be an oil with low-temperature oil.

• Wash the inside of the cabinet with warm water containing detergent. 

• Rinse the cabinet with absolute ethanol, then allows drying.

• Replace the microtome when dry, then reconnect the power.