Odd QC values but not outliers [Bioanalytics]

posted by Ohlbe – France, 2017-09-18 17:53 (2702 d 04:30 ago) – Posting: # 17815
Views: 5,336

Dear Thi Nguyen,

❝ BUT: core run 1 has one LLOQ 498% and one LLOQ 727%, the other four LLOQs have good accuracy 〜100%. Core run 2 has five LLOQs with accuracy 〜100% and one LLOQ 3000%. For core run 2, 3000% can be regarded as outlier (from Grubb's test - calculated by Prism) but for core run 1, both values 498% and 727% are not outliers.


Forget about outlier tests in such situation. The validation is there to demonstrate that your method works. If you exclude those values that may indicate it doesn't, you're losing the plot, whatever the result of the outlier test.

Now there are several possible explanations, including contamination, sample spiking error and carry over. It is rather difficult to comment further without more information. I would go back to the data and look at, for instance:Plenty of possible reasons and aspects to look at. But don't exclude any result unless you have identified what happened... And "we must have made a mistake somewhere" is not considered an "identifiable cause".

Regards
Ohlbe

Complete thread:

UA Flag
Activity
 Admin contact
23,379 posts in 4,913 threads, 1,661 registered users;
284 visitors (0 registered, 284 guests [including 24 identified bots]).
Forum time: 21:23 CET (Europe/Vienna)

Science is what you know.
Philosophy is what you don’t know.    Bertrand Russell

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5