Bioequivalence and Bioavailability Forum • Duplicate LLOQ and ULOQ

Duplicate LLOQ and ULOQ [Bioanalytics]

posted by Helmut – Vienna, Austria, 2012-01-20 14:09 (5256 d 20:05 ago) – Posting: # 7980
Views: 6,156

Dear Ohlbe!

❝ What most people do is that they only use one of the two replicates of the LLOQ and ULOQ samples. Usually the first replicate is used,…

Really most people? That’s strange to me. Why the first and not the second? Why not both?

❝ Some people take whichever value gives the highest R², but I don't like that (I don't consider R² to be a relevant parameter).

Right. R² is meaningless in calibration (if you prefer the statistical term: inverse regression). A nice reference (based on backcalculated concentrations):

Almeida AM, Castel-Branco MM, and AC Falcão
Linear regression for calibration lines revisited: weighting schemes for bioanalytical methods
Journal of Chromatography B 774, 215–22 (2002)

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Helmut Schütz

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Complete thread:

Calibration Curve auditor 2012-01-20 11:15 [Bioanalytics]
- Duplicate LLOQ and ULOQ Ohlbe 2012-01-20 11:59
  - Duplicate LLOQ and ULOQHelmut 2012-01-20 13:09
    - Duplicate LLOQ and ULOQ Ohlbe 2012-01-20 14:26
      - Duplicate LLOQ and ULOQ Helmut 2012-01-20 18:02
        
        Calibration Curve auditor 2012-01-21 05:45
        
        Calibration Curve Helmut 2012-01-21 12:35
        Calibration Curve Ohlbe 2012-01-21 13:44
        
        Calibration Curve Helmut 2012-01-22 21:48