Rotary Microtome and Cryostat Safety Guidelines

Microtomes and cryostats are commonly instruments used in Boston University’s laboratories to section tissues as part of research studies. These instruments pose potential hazards during their use, including when cleaning, handling the blade, and sectioning tissue samples.

Training of Personnel

Personnel must be trained and this training must be documented and provided by a knowledgeable and responsible person within the laboratory before any work is completed. The individual must be assessed for their competency to perform the task safely and properly before being allowed to perform the task independently. Standard Operating Procedures (SOP) should be made available to all users and posted near the point of operation.  In addition to laboratory SOPs users must also familiarize themselves with manufacturer’s manual for their specific piece of equipment.

Potential Hazards:
  • Sharps Injury
    • Microtome blade
    • Microtome blade holder corners
  • Ergonomics
  • Frostbite
    • Histofreeze (aka cytofreeze) and Dry ice if not handled with appropriate PPE (i.e. cryogenic gloves) can lead to frostbite injury.
    • This hazard can be eliminated by using a product called Optimal Cutting Temperature (OCT) which is not known to contain any hazardous materials.
Potential Biohazards associated with paraffin embedded and fresh/frozen tissue samples based on the source of the material:
  • Creutzfeldt-Jakob Disease
  • Scrapie
  • Bovine Spongiform Encephalopathy (BSE)
  • Bloodborne pathogens
  • Other potentially transmissible prion diseases
Sharpness of Blade

A microtome blade is extremely sharp and must be handled carefully.   The rotary handle of the microtome must always be set in the locked position when not in use, changing a paraffin embed tissue block, or replacing or removing the blade. New blade should be placed in the blade holder and secured properly by the clamp before the rotary wheel lock is released. A blade guard placed at each end of the blade must be used to protect the user. Once the blade is seated and secured the rotary wheel lock can be released and the knife and holder advanced to the specimen block. If adjustments need to be made to the specimen, remove the blade from the housing.

Removal of the blade:  Use cut resistant gloves when handling the blade holder and the blade.  Disposable blades must always be removed using forceps or a similar instrument. Do not remove the blade holder from the microtome with a blade present or transport the housing with the blade present. A sharps container must be kept near the instrument to reduce the distance that a blade would be moved. For microtomes with reusable blades, cut resistant gloves must be used when removing and sharpening the blade. EHS recommends using disposable blades whenever possible.

Microtome Cleaning:  Use cut resistant gloves when cleaning the instrument.  The cut resistant gloves must be worn over nitrile gloves when a microtome is being cleaned. Before the microtome is cleaned, the rotary wheel must be locked and the blade removed from the blade holder.  Use caution other components of the microtome may also have sharp edges (i.e. blade holder).

All incidents must be reported.  Please refer to the BU Emergency Instructions posted in your space and available for download at this link for contact information.