Bioequivalence and Bioavailability Forum

Dear Harish!

❝ During study sample analysis, can we set the Area Threshold

❝ parameter based on the LLOQ response? If so, what % of

❝ LLOQ response should be the Area Threshold?

This is a tricky question - especially for LC-MS/MS...
Since I expect your method uses an internal standard (IS), your LLOQ response is based on the ratio of analyte/IS. Therefore it's difficult to set an area threshold for integration - the data system simly 'does not know' the suitable 'LLOQ response' - which in a strict sense can only be established based on the calibration curve for the particular batch.
What you can do is establish some kind of minimum area of the limit of detection (LOD), which generally is 1/3 - 1/10 of the LLOQ. By this you

• avoid integration of artefacts (i.e., noise form the system), and
  
• have quite a large safety margin not to miss integration of values close to the LLOQ.

In any case visual inspection of all chromatograms is a must.
Although the human brain is a perfect pattern recognition system (especially if you have seen many thousands of chromatograms), you should have an SOP in place guiding you through re-integration in a consistent and traceable way.