Chemical Indicators 101: Applications for Use



Since the 1st steam sterilizer was made by Charles Chamberland in 1880, researchers been employed by on solutions to monitor sterilization procedures. It was not before past due 1940s and early 1950s that biological and chemical substance indicators were utilized routinely to monitor the process. At that time, it was stated that no single quality-assurance monitoring method assures that any item is sterile: rather, it assures that the conditions for sterilization to occur were met. That very statement remains valid in todays healthcare environment.

As sterilization processes have evolved and become more complex, so have the monitoring systems that we use. Sterility assurance programs may consist of the following tools that healthcare management can use:

Physical monitoring
Chemical indicators/integrators
Biological indicators
Sterilizer preventative maintenance
Load record keeping This article discusses chemical indicators/integrators (CIs).
Chemical indicators are defined by the Association for the Advancement of Medical Instrumentation (AAMI) as sterilization process monitoring devices designed to respond with a chemical or physical change to one or more of the physical conditions within the sterilizing chamber. CIs are often used to detect sterilizer malfunction/failures resulting from improper loading of the sterilizer, incorrect packaging, deficiencies of the sterilizing agent, or malfunction of the sterilizer itself.

Remember, the pass reading of a CI does not mean that the item or items in the sterilizer load are sterile; it means that the parameter or parameters for sterilization that the CI was designed to measure have been met. The use of CIs is only one portion of a highly effective quality assurance system. They should be found in conjunction with a biological indicator (spore check ), physical monitors, a sterilizer preventative maintenance system, and accurate record keeping for every sterilization load.

Chemical Indicator Classifications

AAMI ST-60 defines five classes of CIs and the precise performance requirements for every.

Process Indicators (Class 1): The standard of chemical indicators, they are referred to as throughput indicators also. These CIs are designed for use with singular items to become sterilized. They are made to demonstrate that that has been subjected to a sterilization procedure and also to distinguish between prepared and non-processed items. Types of Course 1 indicators are tape and the indicators entirely on plastic-type or paper peel pouches.

Indicators for Use in specific Tests ( Class 2): Also known as specialty indicators, Class 2 indicators are designed for use in specific test procedures as defi ned by relevant sterilization standards. Examples of Class 2 indicators are the Bowie Dick and Dart products used in steam sterilizers. These indicators test for the presence of air in the steam sterilizing chamber. A positive test would mean that air, which inhibits the conditions necessary for sterilization, has either not been removed during the cycle or has entered the chamber through leaks in the system. Maintenance must be performed on the steam sterilizer to prevent the presence of air in the chamber throughout a sterilization cycle.

Single-parameter Indicators (Class 3): These indicators respond to among the critical procedure parameters of sterilization and indicate contact with a sterilization cycle in mentioned values of the selected parameter. Important parameters chosen for steam sterilization processes are time or temperature typically.

Multi-parameter Indicators (Class 4): These indicators are more accurate by style than Course 3 indicators. They respond to two or more important parameters of the sterilization procedure and indicate contact with the sterilization routine at explained ideals of the selected parameters. Temperature and period are types of steam sterilization parameters, and concentration and period of ethylene oxide are selected for EO sterilization.

Integrating Indicators (Class 5): These indicators, referred to as integrators, are designed to react to all critical parameters over a specified range of sterilization cycles. Their performance has been correlated to the performance of a biological indicator (BI) under its labeled conditions for use. This class of indicator can be used in place of the BI in many applications, thereby reducing the overall cost of sterile processing.

Use of Chemical Indicators
When considering which class of indicator to use, you must consider your external and internal chemical monitoring needs for your various sterilization systems.

External indicators are accustomed to distinguish between prepared and unprocessed items simply. A Course 1 indicator in the kind of tape, an indicating label, or the indicator legend on a paper or plastic-type peel pouch is suitable and should be positioned on each package that’s designed for sterilization. The exterior CI generally exhibits a straightforward visual color alter that shows the bundle has been subjected to physical circumstances present throughout a sterilization process.

Internal indicators have to be utilized within each package which will be sterilized. According to the complexity of the gadgets and pack within them, a Course 3, Class 4, or Class 5 CI can be used. All internal CIs should be placed in an area of the package that is determined to be the least accessible to sterilant contact. This may not always be in the center of the package.

AAMI states that a Class 5 indicator may serve as the basis for the release of processed items, excluding implants.

Integrator challenge packs utilize a Class 5 chemical integrator within an appropriate challenge pack to monitor sterilization loads. The challenge packs are placed within the sterilization load, outside the packs, in the sterilization chamber, and have been correlated to the kill achieved in the AAMI 16 towel BI test pack. The total result of the chemical integrator enable you to release the load, excluding implantable devices.

Results of exterior indicators and chemical substance integrator challenge packs could be read by the end of the sterilization routine when the bundle is retrieved from the sterilizer. However , inner indicators should be interpreted at the proper time of use. Therefore all healthcare employees ought to be trained on the correct interpretation of a negative and positive result and how to proceed if a poor result occurs.

Be the best Consumer
To become an educated consumer you need to know about the parameters you intend to monitor, which can only help you select the type or class of indicator(s) to purchase. Healthcare management should ask the indicator manufacturer for reliability data and for the security and overall performance characteristics of their products. Questions to ask include:

Are the indicator results easy to interpret?

Can you store the indicator outcomes for a time period?

What sterilization parameters shall the indicator detect?

Is it correlated biologically? If so, what accurately are the specifics (organism, D-value, population)?

Does a shelf end up being had by the indicator lifestyle and what are the mandatory storage conditions?

By asking these simple queries, you shall ensure the right choice of indicators to meet up your quality assurance needs.

John A. Kurowski, BS, RN, is a worldwide clinical education supervisor for STERIS Corporation. He provides education and schooling to STERIS workers and healthcare services in the areas of infection prevention, the proper use of STERIS products, and proper cleaning, decontamination, and sterilization techniques and procedures. He has been a featured speaker for both the local and national Association of periOperative Room Nurses (AORN), the Association for Professionals in Contamination Control and Epidemiology (APIC), and the Society for Gastroenterology Nurses and Associates (SGNA). He is an active person in these organizations.

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