Validation of Enterobacteriaceae

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 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.

Hello Charles.Thank you so much for documents you posted,they were extremely helpful.
Best regards.