On 23 Apr 2009 at 10:41, Jonathan Kay wrote:
> I'd be very interested to hear of any ways that current EQAS force or
> encourage participants to behave in ways that make the processes for
> EQA analysis or information management different from those for
> clinical investigations...
>
> ... reporting styles
> ... running duplicates or rerunning
> ... geting the best analyst to run them
> ... which analyser do you run them on when there are several?
> ... what time of day/ day of week do you run them?
> ... where in relation to analyser start-up/ calibration are they run?
UK NEQAS policy is that EQA specimens should be treated as
patients, and would condemn any effort to give them 'special
treatment' - though some artefactual improvement of apparent
performance may result (but in most cases nowadays the most
reliable process is to put any specimen through the full routine
system), anyone doing so is only deceiving themselves as to the
standard of performance provided to patients
However, this has to be "as far as possible", as some aspects of
physical handling, eg aliquotting, tube transfer or [previously]
reconstitution, may have to differ for practical reasons
The question of "which analyser when there are several" raises a
different issue (though we did find one case where a lab was running
on both and reporting the mean) We usually recommend EQA
participation for each instrument (provided systems allow module
selection by specimen), but for those who only have a single
participation there are three options. Each will yield different
information, which must be remembered when interpreting
performance (and in all cases between-instrument comparability must
be ensured by regular assay on both instruments of clinical
specimens covering the working concentration range)
- analyse on one instrument only [the best performance possible,
equivalent to a lab with only one instrument]
- allow EQA specimens to be run randomly on either instrument
[performance equivalent to clinical specimens]
- force analysis on each instrument alternately [the worst
performance possible - "we can't do worse than this for patients"]
Equivalence between instruments (even the same model) can't be
presumed - it must be checked, and repeatedly rechecked as they
can diverge even if OK initially. And EQA alone is not sufficient -
laboratories must have effective IQC systems, which of course you all
do? . . .
I hope these comments are helpful
David
Dr David Bullock
Director, Birmingham Quality
P O Box 3909, Birmingham B15 2UE, U K
FAX: 0121 414 1179 [+44 121 414 1179]
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