acceptance and bonus info [Bioanalytics]

posted by Ladi – Thailand, 2022-11-15 05:48 (24 d 18:45 ago) – Posting: # 23366
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Hi ElMaestro,

Thank you for your suggestions.

❝ I guess this is your major point.


Yes it is.

❝ On the other hand, one can also argue it does not make sense to inject a run if there are contaminated samples. Much of it boils down to the time by which you conclude there is contamination.


❝ To me, it makes perfect sense to reject a run if there is "contamination" in the blank / zero. The alternative is much worse.


In my opinoin, the guideline do give some room for some imperfections. For example, one of my LQC can have %accuracy > 115% and fail. It could be because of contamination from sample prep. The run still pass as it passes the QC acceptance criteria. For an extreme example, my LLOQ can fail from sample prep. in which the guideline allow me to use 2nd calibration point as LLOQ for the run. I do not have to reject the run. But why such rigid acceptence criteria is applied to the BK and Zero samples eventhough is not explicitly required in the guideline. What about pre-dose samples? If you do both pre-dose without internal standard and with internal standard. Do you reject the run if only pre-dose without internal standard contained some amount of analyte at about LLOQ?


❝ Your SOP is good. If you too often can't comply with it then it may be something else entirely that is your real problem.


I was planning to change it to do duplicate BK and Zero samples. The run fail if both fail as the contamination is consistent. If only one fail, run is accepted as contimination is random. What do you think? However, I won't do duplicate for calibration standards, just BK and Zero.

❝ Quite a few CROs are currently experiencing sporadic carry-over issues with analytes measured in the the pg/mL range. I recommend sponsors to always insist on also having a double blank right after the highest calibrator in the PK-runs and to have some rules in-house for handling situations when there is CO in this injection. CROs really do not like it, simply because they realise their assays at study-time is not behaving as well as it may have been at the time of validation. The solution is certainly not to only insist that CO is assessed as part of the validation, not as part of the study.


Thank you, I like your suggestion. We do have a double blank right after the highest calibrator in every run, but we do not apply any criteria to it yet. Do you suggest same criteria as BK before calibration is applied to it?

Thank you,
Ladi

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