Is biological monitoring adequate for quality assurance in instrument sterilization?

Aug. 1, 2012
The current CDC Guidelines for Infection Control in Dental Health-Care Settings recommend that sterilizers used in dental facilities be monitored "at least weekly."

by Mary Govoni, CDA, RDA, RDH, MBA

The current CDC Guidelines for Infection Control in Dental Health-Care Settings recommend that sterilizers used in dental facilities be monitored "at least weekly."

Although this recommendation is not a law, it is widely recognized by state dental boards as a standard of care for patient safety. But is this weekly biological monitoring, or spore testing as it is commonly referred to, sufficient?

If the test passes, it means that the sterilizer is functioning properly and that instruments have been properly loaded when that particular test was run. However, a biological indicator test can indicate a failure when the sterilizer is functioning properly but is improperly loaded.

In fact, improper loading, especially overloading, is a common cause of sterilizer failure. So shouldn't we be concerned about the many loads of instruments that are processed in between spore tests? Shouldn't we be concerned that every package of instruments has been exposed to the necessary parameters for sterilization? I believe so.

Does each load need to have a biological indicator or spore test? No. This is provided no implantable devices are being processed. But there are chemical or process indicators that can be placed in instrument packs or cassettes to verify that each instrument pack has been exposed to the sterilization parameters - time, temperature, and steam.

There are several types of process indicators, and it is important to know which one is most appropriate to truly implement a higher level of quality assurance for instrument sterilization. Standards for chemical indicators are determined by the Association for the Advancement of Medical Instrumentation (AAMI), the American National Standards Institute (ANSI), and International Organization for Standardization (ISO).

Class 1 indicators are designed to react to one or more of the parameters for sterilization, primarily temperature. These include autoclave tape and labels on sterilization pouches that change color when the instruments are processed. These indicators are meant to distinguish between instruments that have been processed and those that have not.

Class 4 indicators are designed to react to two or more of the parameters, at the appropriate (stated) values (temperature or time) for that parameter. These indicators show that the instruments have been exposed to a sterilization cycle. Class 4 indicators are typically paper strips that are placed in instrument packs or may be printed inside of instrument pouches. ProChek® S Steam Sterilization Integrator from Certol are internal (placed inside instrument packs) and Sure-Check® Pouches from Crosstex are Class 4 integrators.

Class 5 indicators are referred to as integrating indicators, and are designed to react to all the parameters required for sterilization. Class 5 integrating indicators must indicate exposure that is comparable to a biological indicator - 121°C or 250°F for longer than 16.5 minutes. Some examples of Class 5 integrating indicators include STEAMPLUS™ Sterilization Integrator from SPS Medical, the ProChem EXT from Raven Labs, as well as the Sure.

When instrument packs are removed from the sterilizer, each pack should be checked to make sure that the indicator demonstrates a "pass." If not, the instruments should be repackaged and reprocessed.

These indicators should never be confused with or substituted for biological indicators or spore testing. But they are a critical step in daily quality assurance for patient safety.

Using a Class 4 or Class 5 integrator can help determine if each and every instrument pack or cassette has been exposed to the optimal conditions for sterilization. Implementing this additional step in the sterilization process is an important fact to share with patients when you explain to them the steps that are taken to promote safe delivery of dental care.

Mary Govoni, CDA, RDA, RDH, MBA, is the owner of Mary Govoni & Associates, a consulting company based in Michigan. She is a member of the Organization for Safety, Asepsis and Prevention. She can be contacted at [email protected] or

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