Bioequivalence and Bioavailability Forum

Dear TK,

❝ Further question, let's say that our calibration curve range is 2-800 ng/mL with LQC at 6 ng/mL, MQC at 400 ng/mL and HQC at 750 ng/mL.

Preliminary observation regarding your HQC: the upper limit of the acceptance range (750 + 15 %) is 862 ng/ml, which is above your ULOQ. You will certainly get some results above 800 ng/ml, but as you are not supposed to extrapolate above the ULOQ you won't know whether they pass or fail. Your HQC concentration should not be above 695 ng/ml (upper acceptance limit 799 ng/ml).

Regarding your MQC you have 2 options:
- add another QC level, at a lower concentration (let's say 150 to 200 ng/ml)
- lower the concentration of the existing MQC sample. 30 % of the ULOQ would be 240 ng/ml. A concentration of 240 to 300 ng/ml should be fine for most subjects.

Of course you could also lower the ULOQ and adjust the MQC and HQC concentrations accordingly, but then you would have higher chances to have to dilute samples.

In the end you will also have some ISR data which will show how the method performs.