How Often Should I Perform Sterilizer Monitoring?

According to the Centers for Disease Control and Prevention (CDC),sterilization procedures should be monitored through a combination of mechanical, chemical, and biological techniques designed to evaluate the sterilizing conditions and the procedure's effectiveness.

The most common testing procedures include:

1)    leak rate test,

2)    bowie Dick type air removal test,

3)    chemical indicators, biological indicators,

4)    process challenge devices,

5)    physical tests.

Mechanical techniques for monitoring sterilization include assessing the cycle time, temperature, and pressure of sterilization equipment by observing the gauges or displays on the sterilizer.

Chemical indicators, internal and external, use sensitive chemicals to assess physical conditions.  Because chemical indicators do not prove sterilization has been achieved, a biological indicator like a spore test is required.

Biological indicators (BIs) are the most accepted means of monitoring the sterilization process because they directly determine whether the most resistant microorganisms like the Geobacillus or Bacillus species, are present. Chemical and mechanical indicators merely determine whether the physical and chemical conditions necessary for sterilization have been met.

Biological monitoring (BI), spore testing, should be done on a weekly basis, to verify the correct functioning of sterilization cycles. Weekly testing is the minimum and more frequent testing may be required.  Follow manufacturing directions with respect to correct placement of the BI in the sterilizer.  When monitoring, a control BI not processed through the sterilizer but from the same lot as the test indicator, should be incubated with the test BI. The control should yield positive results for bacterial growth.

In addition to routine biological monitoring, additional testing is necessary and should be conducted after: 

1)    a new type of packaging material or tray is used,

2)    training new sterilization personnel,

3)    a sterilizer has been repaired,

4)    changes in the sterilizer loading procedures. 

Ultimately, monitoring frequency is the responsibility of the user, but should follow manufacturing guidelines.