What type of testing device should I use?
Process, Specific,
Multi-Variable, Integrating,
Emulating & Biological
The Six Indicator types
It is important to bear in mind that each of the six categories has specific characteristics that determine where and how the indicators should be used. This also determines the level, depth and kind of information provided, so do be sure that you choose the right type of indicator for what you want to achieve.
The following information taken from the AS:NZS 4815
To get a copy go to the standards site and search 4815 or 4187 to find the relevant standards for your practice
7.7.5 Chemical indicators
7.7.5.1 Classes of chemical indicators
Chemical indicators are designed to monitor one or more sterilization process parameters for the purpose of detecting equipment malfunction or sterilization process failures (or both).
ISO 11140-1 outlines six different classes of chemical indicators, as follows:
(a) Class 1 – Process indicators e.g. sterilizer indicator tape.
These are intended for use with individual units, e.g. packs, containers, to demonstrate that the unit has been exposed to the sterilization process and to distinguish between processed and unprocessed units.
(b) Class 2 – Indicators for use in specific tests e.g. Bowie Dick type tests.
These indicators are designed for use in specific test procedures as defined in this Standard.
(c) Class 3 – Single parameter indicators e.g. temperature
These are designed for one of the critical parameters essential to the sterilization process, and indicate exposure to a sterilization cycle at a stated value of the chosen parameters.
(d) Class 4 – Multi-parameter indicators e.g. time and temperature
These are designed for two or more critical parameters and indicate exposure to a sterilization cycle at stated values of the chosen parameters.
(e) Class 5 – Integrating indicators e.g. time, temperature and moisture
These are designed to react to all critical parameters over a specified range of sterilization cycles. The stated values are those required to achieve a stated inactivation by referring to a stated test organism with stated D and, if possible, z values.
(f) Class 6 – Emulating indicators (cycle verification indicators) e.g. 134°C for 3.5 min in steam.
These indicators are designed to react to all critical parameters over a specified range of sterilization cycles for which the stated values are based on the settings of the selected sterilization cycles.
Below are an overview of Albert Browne types designed for the Class types mentioned above
Process Indicators - Class 1
Browne Process Indicators are usually placed on the outside of the tray, pack or pouch so that processed and unprocessed items can be identified at a glance. They give users assurance that the tray, pack or pouch has been exposed to a particular process, e.g. steam, ethylene oxide etc. but cannot provide quantitative
information about the process or determine how effective it has been. They are sometimes referred to as ‘exposure control’ or ‘throughput’ indicators.
Specific-Use Indicators
Browne specific-use indicators are designed for use in two fundamental areas; in specific test procedures defined in relevant standards and guidance documents and in monitoring defined stages of a process that would otherwise be difficult to routinely assess. Mechanical equipment used throughout the decontamination process will have undergone validation before being sanctioned for daily use. Most machines equipped with electronic or mechanical sensors to record specific aspects of the machines activity. These sensors are connected to monitoring and recording gauges, graphical charts and digital displays that provide fundamental information on the machine’s performance. Although providing vital information on the machine’s mechanical activity, they cannot provide monitoring of the physical
conditions occurring inside the chamber of the machine. Furthermore, between scheduled maintenance visits, these sensors, monitors and recorders can lose calibration. Browne specific-use indicators can help resolve these two issues by
providing supplementary data on critical aspects/stages of a process.
Multi-Variable Indicators - Class 4
Browne Multi-Variable Indicators are the first of three types of indicator available for ‘in-pack’ monitoring and like the others are placed inside each tray, pack or pouch before processing. These indicators will change colour when exposed to the sterilant / disinfectant providing users with clear visual reassurance that the agent has penetrated to the point of placement in each tray, pack or pouch.
Integrating Indicators - Class 5
Browne Integrating Indicators are the second of three types of indicator available for ‘in-pack’ monitoring and like the others are placed inside each tray, pack or pouch before processing. The indicators will change colour when exposed to a sterilant / disinfectant in sufficient quantity or duration to inactivate the equivalent
challenge presented by a defined and stated test organism. This provides users with clear visual reassurance that the agent has penetrated to the point of placement in each tray, pack or pouch.
Emulating Indicators - Class 6
Browne Emulating Indicators are the third of three types of indicator available for ‘in-pack’ monitoring. Emulating Indicators provide the most specific information of any chemical indicator available and like the others are placed inside each tray, pack or pouch before processing.