Standard Operation Procedures: Mouse Microisolator Cage, or Individual Ventilated Cage, Change (Extracted from an actual SOP)

Purpose: To describe the procedures for changing mouse static microisolator cages, or individual ventilated cages from a ventilated rack.

General Information

All persons working with animals must adhere to the following standard operating procedure. All personnel who work with microisolator caging will be trained by ACS (Animal Care Services) to ensure that the barriers are properly maintained. Entry into the facility is limited to those persons that have been previously trained and have permission from the ACS Director.

Mice that are taken out of the facility for any reason will not be allowed to return.

All mice entering the facility must have complete health records accompanying the shipment. Mice shipped into the SPF (Specified Pathogen Free) facility must arrive in undamaged filtered crates to be acceptable. Shipping crates must be opened only by ACS staff for transfer to microisolator caging.

Cage Examination

Examine cages prior to each use to ensure that they are in good repair (e.g., no cracks). Stainless steel lids should be free of any sharp edges or loose bars. The microisolator filter tops must be intact and dry.

Equipment and Materials

  • Laminar Flow (Class II Biological Safety Cabinet) Cage Change Station
  • Spray bottle with disinfectant - Clidox® mixed as per instructions
  • Sterile supplies of diet, bedding and waters
  • Sterilized waste containers, paper towels and other required supplies
  • Specific equipment required for intended procedures, pre-sterilised

Changing Cages

NOTE: All manipulation of mice and cages must be performed in the laminar flow hood (Class II Biological Safety Cabinet).

  • Put on booties, gown, face mask, hair bonnet, and gloves upon entering each room.
  • Prepare a container of disinfectant following label instructions for dilutions.
  • Make sure that the laminar flow hood is turned on and operational. Check the gauges to make sure.
  • Prior to use of the hood for any reason, spray all surfaces inside the hood with Clidox®.
  • Place a container of disinfectant inside the hood for dipping hands between dirty and clean cages.
  • Bring the necessary pre-sterilized cages complete with bedding and feed on a clean cart to the change hood.

Change one cage at a time as follows: remove dirty cage from the rack and place it in the hood; place a clean cage beside the dirty cage in the hood; remove the microisolator bonnet from the dirty cage; place the dirty bonnet bottom side down under the hood; remove the cage card holder from the dirty cage and place it on the clean cage; remove the dirty water bottle from the wire bar lid and remove the wire bar lid; transfer the mice to the clean cage using a disinfected forceps; place the wire bar lid on the clean cage; fill the hopper with feed and place fresh water bottle on cage; replace filter bonnet on cage.

Submerse hands in the disinfectant solution, and repeat for next cage.

Change gloves between each group or type of animal (e.g., between different investigators, different strains, or different protocols).


  • Daily: Empty trash and replenish supplies as needed, on a daily basis. Keep the room neat, clean, and clutter-free. Record all activities on the room logbook.
  • Weekly: Disinfect animal room floor with disinfectant once per week.
  • Monthly: Disinfect walls, light fixtures, cabinets, and cage racks. Change air filters.

Receiving New Shipments

Unopened cartons of animals will be taken directly to the facility. Prior to entering a room, the exterior of the carton will be sprayed with Clidox® until wet. Allow the container to sit for 10 minutes before taking it into a room.

Spray the shipping crate again with Clidox® and put into the laminar flow change hood. Gently make an opening in the top of the shipping carton with scissors. Using forceps that have been disinfected pick up the individual mice by the base of their tails and transfer them from the shipping carton into the sterile cage. Follow the standard cage changing procedure.