Chemical indicators based on the reactivity of inks that change color when subjected to sterilization processes by gamma or beta radiation and X-ray:
ISO 11140-1:2014 regulates chemical indicators used for 3 main applications:
- To allow differentiation between unprocessed and processed items
- Carry out specific tests such as the Bowie-Dick test
- Evaluate the achievement of the critical parameters of the sterilization process at the positioning point.
Attainment of the chemical indicator’s end point should not be regarded as an indication of attainment of an acceptable sterility assurance level, but rather one of many factors which should be taken into consideration when judging the acceptability of a sterilization process.
ISO 11140-1:2014 divides chemical indicators into 6 classes, grouped into 3 macro-categories depending on the intended use:
- Process indicators: they serve to distinguish products that have undergone the cycle from those that have not. An example is the indicator tape
- Indicators for specific test: for example the Bowie-Dick test
- Parametric indicators, integrators and emulators: indicators designed to react to critical process parameters and indicate exposure at a set value for each parameter. For example, strips with a band that changes color in the presence of specific combinations of time-temperature-vapour quality.
