Hi everybody.
I am currently working on a validation of SRPS ISO 21528-2:2009 standard method for enterobacteriae. And I got to the part of repeatability and reproducibility,and did the calculations with our result. But,in the standard are not listed the acceptable limits,to which I can compare my results to. What do you do in this situation? Where can I find limits for repeatability and reproducibility?
Hi Janie,
I have no direct experience this topic or familiarity with iso21528, iso16140.
Does iso21528 reference the iso16140 standard as the appropriate source for repeatability/reproducibility criteria ? The latter standard seems to have gone through at least 2 revisions (2011, 2016) which include defs such as the following which you probably know already -
Repeatability limit ®: value less than or equal to which the absolute difference between two measurement results obtained under repeatability conditions is expected to be with a probability of 95%
Reproducibility limit ®: value less than or equal to which the absolute difference between two measurement results obtained under reproducibility conditions is expected to be with a probability of 95%
I found a few (claimed) practical examples of above / use of iso16140 which have attached below but no idea if these relevant or not, eg -
vali1 - afnor validation, iso16140, enterobacteriaceae enumeration,2008.pdf 554.48KB
38 downloads
vali2 - NF validation, iso 16140, enterobacteriaceae enumeration 2014.pdf 960.83KB
36 downloads
However I also noticed this comment in another NF document dated 2012 -
NOTE 1 : Criteria of acceptability of results
The standard EN ISO 16140 sets no result acceptability threshold for the different criteria tested. It falls to the third party validation organisations using this protocol to examine and assess the results for each of these criteria, and supply an opinion on their acceptability.
