Sterilization Indicators Inside Packages

Indicator tape is designed and intended to be used on the outside of packages as an external indicator and should not be placed internally.   External indicators applied to the outside of a package, such as chemical indicator tape or special markings, change color rapidly when a specific parameter is reached, and they verify that the package has been exposed to the sterilization process. Some external indicators change color long before appropriate sterilization conditions are even met.   Autoclave tape is an example of an external indicator that can be problematic at times because it often changes to show the striped pattern following a brief exposure to steam. External indicators do not guarantee that sterilization has been achieved or even that a complete sterilization cycle has occurred. External indicators are primarily used to identify packages that have been processed through a heat sterilizer, thus preventing the accidental use of unprocessed items.1    Internal indicators should be used inside each package to ensure that the sterilizing agent has penetrated the packaging material and actually reached the instruments inside. Internal chemical indicators are sometimes referred to as multiparameter indicators if they are designed to react to two or more parameters (e.g., time and temperature; or time, temperature, and the presence of steam). A multiparameter internal chemical indicator can provide a more reliable indication that sterilization conditions have been met.1    We would like to refer you directly to the Centers for Disease Control and Preventions (CDC) Guidelines for Infection Control in Dental Healthcare Settings, which state the following:
Chemical indicators, internal and external, use sensitive chemicals to assess physical conditions (e.g., time and temperature) during the sterilization process. Although chemical indicators do not prove sterilization has been achieved, they allow detection of certain equipment malfunctions, and they can help identify procedural errors.

External indicators applied to the outside of a package (e.g., chemical indicator tape or special markings) change color rapidly when a specific parameter is reached, and they verify that the package has been exposed to the sterilization process. Internal chemical indicators should be used inside each package to ensure the sterilizing agent has penetrated the packaging material and actually reached the instruments inside. A single-parameter internal chemical indicator provides information regarding only one sterilization parameter (e.g., time or temperature).

Multi-parameter internal chemical indicators are designed to react to >2 parameters (e.g., time and temperature; or time, temperature, and the presence of steam) and can provide a more reliable indication that sterilization conditions have been met. Multi-parameter internal indicators are available only for steam sterilizers (i.e., autoclaves).2

Additionally, many pouches on the market now feature built in internal and external indicators, which Dr. Chris Miller said is an advancement that saves clinicians time and money previously spent purchasing and inserting indicator strips into the pouches.3    Utilizing sterilization pouches/bags with built in internal and external indicators eliminates the need to insert another indicator strip into the bag. However, dental infection control experts do recommend that the sterilization pouches contain built in internal/external multi-parameter steam indicators verses those that only measure one parameter.   Resources:
1) Practical Infection Control In Dentistry, 3rd. edition. By Molinari and Harte. Kluwer/Lippincott/Williams & Wilkins Publishers. Copyright 2010. Page 160.
2) CDC Guidelines for Infection Control in Dental Healthcare Settings (December 2003) http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5217a1.htm
3) Dental Products Report: http://www.dentalproductsreport.com/articles/show/dpr0709_stm_sterilization-pouches/2
For the most current information on infection control issues, please join us in Tampa, Florida, June 10-13, 2010, for the OSAP Annual Symposium. This information is also available on the OSAP website. 

OSAP FAQ Department; office@osap.org