Chemische Indikatoren der Klasse 6 und ihre «stated values»: Eine Prüfung von sechs Fabrikaten

Translated title of the contribution: Six commercially available Class 6 Chemical Indicators tested against their stated values

Research output: Contribution to journalArticleAcademicpeer-review

4 Citations (Scopus)


Objective: To assess whether ISO 11140 part 1 class 6 Chemical Indicators (CIs) for steam sterilization actually meet their claimed Stated Values (SVs). SVs for steam sterilization represent a temperature-time combination at which the CI has to give an unambiguous pass result, e. g. at 134°C after 3.5 minutes in saturated steam. Design: Six types (brands) of commercially available ISO 11140 part 1 class 6 CIs were purchased and investigated. These CIs were exposed to saturated steam at 134°C. The exposure time was varied from 1 s to 15 minutes. At the SVs of the indicator it has to show an unambiguous color change towards the reference color. This color change indicates a pass result. Method: After exposure of the CI s to saturated steam the indicator ink and the reference color on the CI strip were read out immediately. To avoid observer-dependent results these readings were obtained from a spectrodensitometer. Results: Only one type of the six class 6 CIs actually reached its reference color and showed a color change close to its SVs. Conclusions: Class 6 CIs have only a very limited added value and in most cases their use may lead to conclusions that are unreliable and even unsafe.

Original languageGerman
Pages (from-to)395-404
Number of pages10
JournalZentralsterilisation - Central Service
Issue number6
Publication statusPublished - 1 Dec 2012

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