The Principles of Medical Device Decontamination

CIs are categorised into different types and their response to the process variables of a sterilization process will depend on which type they are. CIs come in many forms depending on how they will be used and are described in the BS EN ISO 11140 series of standards. There are six types of CI specified in BS EN ISO 11140-1 7 . These are shown in Table 11.1

CI Type Title

Description

For use with every pack to distinguish processed from unprocessed load items

1

Process Indicator

Intended for use in specific tests defined in relevant sterilizer/sterilization standards (e.g. Bowie and Dick Test described in EN ISO 17665 8

2

Special Test Indicator

Reacts to one of the process variables of the sterilization process

3

Single Variable Indicator

Reacts to two or more of the process variables of the sterilization process

4

Multi Variable Indicator

Reacts to all of the process variables of the sterilization process that mimic the response of a biological indicator Reacts to all of the process variables of the sterilization process giving a result related to the standard exposure conditions specified in a sterilization standard e.g. 132 for 4 minutes

5

Integrating Indicator

6

Emulating Indicator

Table 11.1 The six types of CI described in EN ISO 11140-1:2014

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