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The following message was posted to: PharmPK
Dear all,
Thanks for your suggestion regarding calibration curve.
Today we have faced another problem that two high QC samples in the
analytical run has found to be out of 15% of the nominal value
because of
processing error. If I use previous calibration equation, one low QC
sample
found to be out of 15% of nominal value. Is it allowed to use another
calibration equation? or else should I repeat all the plasma samples?
Regards
Saji
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Dear Saji,
Unfortunately, it appears that you have insufficient number of QC
results to verify that the run was performing properly. You might be
able to use a different equation by first verifying that all the data
in your validation runs for the method give acceptable results with
the alternative calculation and documenting it in a validation
report. But it will still be very difficult to convince anyone that
you are not simply trying to manipulate the data in order to get the
result you want.
Unless it is impossible to repeat the analyses, I would document the
run as not valid because of insufficient acceptable QC results and
reanalyze the samples.
Original question:
Today we have faced another problem that two high QC samples in the
analytical run has found to be out of 15% of the nominal value
because of processing error. If I use previous calibration equation,
one low QC sample found to be out of 15% of nominal value. Is it
allowed to use another calibration equation? or else should I repeat
all the plasma samples?
Tom
Thomas L. Tarnowski, Ph.D.
650 692-9296
ttarnowski1.-at-.aol.com
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Another calibration equation is possible, probably life-saver in your
case. Parabolic, log parabolic and reverse parabolic equations are
feasible. But you must prove their use is scientific and brings more
insight into the calibration. Consult statistical books for the
equations. Bets luck.
Ilbeyi
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