Chemical indicators are one of the three critical devices for monitoring a sterilization process.  They are designed to respond with a characteristic chemical or physical change to one or more of the physical conditions within the sterilizing chamber.  Chemical indicators are intended to detect potential sterilization failures immediately that could result from incorrect packaging, incorrect loading of the sterilizer, or malfunctions of the sterilizer.  The Association for the Advancement of Medical Instrumentation has defined five classes of chemical indicators: Class 1 (process indicator); Class 2 (Bowie-Dick test indicator); Class 3 (single-parameter indicator); Class 4 (multi-parameter indicator); and Class 5 (integrating indicator).

FDA defines a physical*/chemical sterilization process indicator (21 CFR 880.2800(b)) as: A device intended for use by a health care provider to accompany products being sterilized through a sterilization procedure and to monitor one or more parameters of the sterilization process. The adequacy of the sterilization conditions as measured by these parameters is indicated by a visible change in the device.

Compared to biological indicators:

In one study, chemical indicators were more likely than biological indicators to inaccurately indicate sterilization at marginal sterilization times (e.g., 2 minutes). Chemical indicators should be used in conjunction with biological indicators, but based on current studies should not replace them because they indicate sterilization at marginal sterilization time and because only a biological indicator consisting of resistant spores can measure the microbicidal killing power of the sterilization process.

Placement of chemical indicators:

Chemical indicators are affixed on the outside of each pack to show that the package has been processed through a sterilization cycle, but these indicators do not prove sterilization has been achieved.  Preferably, a chemical indicator also should be placed on the inside of each pack to verify sterilant penetration. Chemical indicators usually are either heat-or chemical-sensitive inks that change color when one or more sterilization parameters (e.g., steam-time, temperature, and/or saturated steam; ETO-time, temperature, relative humidity and/or ETO concentration) are present.  If the internal and/or external indicator suggests inadequate processing, the item should not be used.  An air-removal test (Bowie-Dick Test – a Class 2 indicator) must be performed daily in an empty dynamic-air-removal sterilizer (e.g., prevacuum steam sterilizer) to ensure air removal.

IMPORTANT NOTE:  The “pass” response of a chemical indicator does not prove the item accompanied by the indicator is necessarily sterile. 

Indicators come in many different forms including on autoclave tape, labels, pouches, Bowie-Dick Tests and more (see Supplies for our complete list). 

DID YOU KNOW?

§       Autoclave Testing Service, Inc. is one of the first companies nationwide to offer a Mail-In sterilizer monitoring service using biological indicators.  Serving the healthcare industry throughout the United States and Canada since 1986, we have thousands of satisfied customers.

§       We have on-line test results allowing you to access your results at your convenience!  Your Sterilizer Test Report (STR) is posted on-line upon completion of culturing, offering minimum turn-around time.

§       We have 24-hour test results for Steam sterilizers!

§       We have a comprehensive Glossary of Terms related to the sterile processing area (scroll below to view the Glossary).  This is invaluable information, assisting you with this important area of your facility.

ATS, Inc. now stocks sterilization pouches, sterilizer cleaners, chemical indicator products, sterilizers (new and used), ultrasonic cleaners, water distillers, and more!  (see Supplies).