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Thank you for your reply.
I feel that you misinterpreted my comments regarding the placement of
I guess it is a matter of "how comfortable" you are with the
placement of QC and the difference between the various level.
Would I feel comfortable with a difference of 250 between the lowest
and mid level QC? My answer is no.
I would most likely add another level in between to reduce the
difference between the two.
This is personal but at the same, we need to ask ourself if we need
to follow the FDA guidelines blindly or can we as scientist make our
assay more robust by adding more QC levels and using trending during
the various validation test in comparison to the recommended low and
high QC levels by the FDA?
I have also been involved with FDA audits and they have never
complained that we were doing more work than they actually recommend
in their guidelines.
Comments/observations are more than welcome.
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The following message was posted to: PharmPK
The placement of QC is relatively simple. Guidance requests the LQc
must be <= 3X the LLOQ, the new crystal city indicates the HQC must be
at 75% of the ULOQ. The MQC can be at the arithematic mean, geometric
mean or median of the points between and including the LLOQ and ULOQ.
geometric mean ( propsed by crystal city) will be closer to 25-30% of
the range,as will the median. The arithmatic mean is at about 50%
However there is nothing preventing addition of other QCs such as a LMQC
and an HMQC except limiation on the plate or autosampler
Ed O'Connor, PhD
Technical Director, Immunoanalytical
115 Silvia Street
West Trenton, New Jersey
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