Washer Disinfection

Washer disinfectors are a requirement to achieve Best Practice compliance.

Washer Disinfection

Automatic washer disinfectors are the preferred method of cleaning instruments and medical devices. Critical cycle parameters are fully controlled, repeatable and a record of the cycle is usually available via printout or memory card. The process is fully automated. Washer disinfectors both clean and disinfect consecutively during a process cycle.

Washer disinfectors are a requirement to achieve best practice compliance.

A typical washer disinfector cycle for instruments includes the following five stages: 


Removes “difficult” gross contamination, including blood, tissue debris, bone fragments and other fluid and solid debris. Latest standards indicate that a water temperature of less than 45°C is used to prevent protein coagulation and fixing of soil to the instrument. 


Removes any remaining soil. Mechanical and chemical processes loosen and break up contamination adhering to the instrument surface. Detergents used in this process must 
be specified by the manufacturer as suitable
for use in a washer-disinfector and compatible with the quality of water used. Detergents should also be compatible with the instruments being processed to avoid instrument degradation including discoloration, staining, corrosion and pitting. 


Removes detergent used during the cleaning process. This stage can contain several sub-stages. The quality of water to be used for this stage is an important consideration in terms of ensuring a clean unmarked product after sterilization. Advice should be taken from manufacturers with respect to the compatibility of the hardness or quality of the water supply with the equipment and detergents used. 

Thermal Disinfection

The temperature of the load is raised and held at the pre-set disinfection temperature for the required disinfection holding time, for example 80°C for 
ten minutes or 90°C for one minute. 


Purges the load and chamber with heated air to remove residual moisture. 

The Main Points to Consider

The washer disinfector should be operated in accordance with the manufacturer's instructions and local protocols.

  • If necessary, carefully wash heavy soiling off the instruments prior to placing in the washer disinfector. 
  • Load the washer disinfector as specified by the manufacturer.
  • Place in the washer disinfector basket in a single layer with hinged instruments open.
  • Instruments should not overlap as this will reduce the cleaning action.
  • If used, connect the hand pieces to the relevant adaptors. Check with your hand piece manufacturer that they are suitable for cleaning in a washer disinfector.
  • Ensure that any filters are in place.
  • Before closing the door verify that the rotors are free to rotate.
  • Close the door and initiate the correct washing cycle.
  • On completion of the cycle, verify that the cycle parameters have been achieved before unloading the machine.
  • Record the cycle parameters in the washer disinfector log book.

For more information on testing and validation of washer disinfectors please see the relevant sections of the Isopharm website.