Comparison Study required or not for an Approved Method?

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Comparison Study required or not for an Approved Method?

Postby kchapman1 » Wed Jun 22, 2011 11:53 am

A lab in our area (Texas) recently received a nonconformance for not completing a comparison study between Colilert 18 and membrane filtration for total coliform analysis. Does anyone know if this is a requirement of either the 2003 or 2009 lab standard or is a method requirement? I know of many labs who have never performed a study because Colilert is an accredited / acceptable / approved method for the analysis of total coliforms. Any guidance on the need for a comparison study would be appreciated.
kchapman1
 
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Re: Comparison Study required or not for an Approved Method?

Postby kchapman1 » Wed Jun 22, 2011 11:59 am

The SLAG group has been discussing this question and the comments are to the point that (1) New York does not require a comparison study for using Colilert-18 (one from a Lab, another from an assessor); (2) This sort of study does not seem to be required by either the 2003 or 2009 Standard; however, there may (?) be a requirement to do so in 40CFR141.
kchapman1
 
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