Article written by
Tom Coyner, President, Analytical Products Group
We recently had the opportunity to
participate in two separate international events. The first was the
International Laboratory Accreditation Cooperation (ILAC) meeting in
New Zealand and later the EURACHEM PT Conference in Slovenia. They
have re-enforced our view of the purpose of PT programs.
Proficiency
Testing is a fundamental part of virtually all laboratory
accreditation schemes and is required by ISO 17025. However, the
international view of proficiency testing is dramatically different
than ours in the States. Throughout the world PT is being used to
improve laboratory performance rather than as in the States where it
is used as a regulatory “hammer” to remove labs that perform poorly.
This gap is so large that in many of the ILAC meetings I sat quietly
and shook my head. Why, how did this happen?
As any man will tell
you, you can drive a wood screw in with a hammer easier than with a
screwdriver; just don’t expect it to stay. I think that’s our
problem with PT programs. We have a really excellent tool that we
are using for the wrong application. However, we always believe that
we can do anything so we have spent years modifying PT programs to
meet “our needs” without realizing that what we ended up with might
not still be a PT program.
Laboratory accreditation implies a
determination of technical competency to perform the analyses for
which the lab is accredited. This is normally done through the
auditing process. The purpose of the PT programs is to verify for
the laboratory, not the accrediting authority, that they are getting
results which demonstrate sufficient accuracy and precision when
compared to other similar labs. The labs understand that it is their
responsibility to insure the quality of their data.
In contrast, the
U.S. system is used by the regulatory authority as an enforcement
action and any deviation from acceptable results is immediately
punished by withdrawal of certification. Furthermore, the PT
acceptance limits established, first by USEPA and later by NELAC, do
not demonstrate accuracy and precision but rather measure
performance to arbitrary criteria unrelated to regulatory limits.
The system does not even allow labs to compare performance against
their peers since that information is never reported.
Over the
course of the next few months, I will explore some of the key
benefits of a true interlaboratory PT program as used by the
rest of the world and detail the many contrasts with
the U.S. program. I am hopeful that this will help laboratories to
understand what they are missing by not requiring their regulators to
have technically sound programs.
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