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I would like to know the opinion of yours about blank samples that are used to spike the calibration
curve and CQs.
Is there any problem if I use samples of one study as blank for another one?
For example I have samples of one study with drug X. Could I use this samples as blank, for analyses
samples of drug Y? Could I use the samples of drug X to make my calibration curve of study with drug
Y?
Thanks for your attention,
Kelen
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Why? Blank Matrix is a reagent and has to be tested before use. You would need to do the same with
surplus and indicate that the material was handled and tracked carefully. Sampled before and after
pooling. It is, in my opinion, not worth the risk.
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Analytical method should be selective for UV, fluorescence, or for other detection methods. If your
method is complance with this you could evaluate for complete validation.
If your detection methods is MS/MS you should evaluate ionic interference, if analyte or IS signal
increases or decreases, you can not use that matrix.
José Hernández
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Hi,
Generally, using blanks from the same study allow for assurance of the
within-study suitability of the assay. Commonly assays are developed
and ensure that the expected commonly-coadministered drugs do not
interfere. Using samples from the same study can approximate the lack
of interference of any drugs administered in that study.
So, it is best practices to use within-study blanks for this reason.
Have a good day,
Bill
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In practice we don't do this. because no one know about the stability and interference/interaction
of these drugs and standards.
Dr. Zafar
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Dear Kelen,
Assay of PK samples from Clinical studies should follow GCP rules. As consequence, it is forbidden
to use plasma samples from subjects who participated to "X" clinical study for the preparation of
calibrator and QC of a "Y" study, as the volunteers have signed a informed consent.
K regards
Bernard Jeanbaptiste, MSc.
SGS Life Science Services
Test Facility Management Representative,
Bioanalysis Department Manager, Laboratory Services
SGS Belgium sa
Vieux Chemin du Poète, 10
1301 Wavre - Belgium
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Even if that use was captured in informed consent, I would hesitate to use.
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